Methylene Blue: Parasites, Cancer and Safety

Table of Contents

1. What the Presentation Said
2. What Methylene Blue Is and What It Is Approved For
3. Malaria: The Human Trials
4. Other Parasites: Laboratory Work and Single Cases
5. Cancer Research: Photodynamic Therapy Needs Light
6. In Cancer Surgery and Supportive Care
7. The Red-Light Combination
8. Vein, Mouth or Skin: What Happens in the Body
9. Is It “Non-Toxic”? What the Label Records
10. Glucose-6-Phosphate Dehydrogenase Deficiency: How Common Is It?
11. Serotonin Syndrome: Not Only Monoamine Oxidase Inhibitors
12. How the Claim Compares With the Research
13. What Is Not Known
14. Connections
15. Key Research Papers
16. Featured Videos

What the Presentation Said

Near the end of the presentation, after discussing ivermectin and mebendazole, the speaker said that Methylene Blue was worth considering for its antiparasitic mechanisms and benefits, which the speaker described as extensive. The speaker said they had used it extensively themselves. The points made were:

• Benefits listed: mood enhancement, support for mitochondria (the energy-producing parts of cells), immune defence and antimicrobial action. In the question session the speaker added that it is antiparasitic, antiviral and antimicrobial, and helps people with “chemo brain”, age-related cognitive decline and memory loss.
• Ways it is given: into a vein (which the speaker said is done at the speaker’s clinic), under the tongue or by mouth, and also topically on breast tumours, lymph nodes and similar sites.
• How the body handles it: the speaker said it crosses the blood-brain barrier, is broken down by the liver and leaves in the urine, which turns slightly bluish or green-tinted.
• Safety: the speaker called it “harmless and highly effective” and, later, “non-toxic”, “generally well-tolerated”, with occasional dizziness, nausea, headache or stomach discomfort, which the speaker said the clinic seldom sees.
• Two cautions: the speaker said it is not given to people lacking the enzyme glucose-6-phosphate dehydrogenase (G6PD) — nor is vitamin C in that case — but called this deficiency very rare, seen in perhaps one in every thousand patients. The second caution named was taking an antidepressant that is a monoamine oxidase inhibitor (the transcript’s wording is garbled here). The speaker also told listeners to review any medication with a doctor first.
• Red light: asked whether daily red-light therapy helps breast cancer patients and whether Methylene Blue works only with red light, the speaker said that pairing Methylene Blue with red light gives a “synergistic effect”, described the light as near-infrared in the 616 to 680 nanometre range, and said red light improves blood flow in small vessels, lowers inflammation and is “very healing”.

The presentation cited no study for any of these Methylene Blue statements. It did not name a specific parasite that Methylene Blue treats, and it did not say what cancer outcome it was expected to change. This page therefore tests each statement against what has been published.

What Methylene Blue Is and What It Is Approved For

Methylene Blue (chemical name methylthioninium chloride) is a dye that switches easily between a blue form and a colourless form by gaining or losing electrons. That chemistry is why it can reverse methemoglobinemia, a condition in which the iron in haemoglobin is changed into a form that cannot carry oxygen.

The current US label for Methylene Blue injection lists one use: the treatment of acquired methemoglobinemia in children and adults, approved under the U.S. Food and Drug Administration’s accelerated-approval pathway (U.S. Food and Drug Administration (FDA) label, 2023). Other medical uses — as a surgical dye, for low blood pressure after heart surgery, for a brain toxicity of the chemotherapy drug ifosfamide — are off-label. The site’s main Methylene Blue page covers these uses and the mitochondrial and brain research; this page keeps to parasites, cancer and safety.

The antiparasitic history is real. In 1891 the physicians Paul Guttmann and Paul Ehrlich reported treating malaria patients in Berlin with Methylene Blue, and a 2018 systematic review calls it the first synthetic antimalarial ever discovered (Lu and colleagues, 2018). The story is told in detail on the Ehrlich and phenothiazines history page and the history and discovery page.

Malaria: The Human Trials

Malaria is the one parasitic disease in which Methylene Blue has been tested in randomised trials in people. Malaria is caused by Plasmodium parasites that live inside red blood cells; see the site’s malaria page.

The systematic review

A 2018 systematic review in BMC Medicine searched the literature to early 2017 and found 21 studies reporting on 1,504 malaria patients, two-thirds of them children (Lu and colleagues, 2018). Older studies were case series of Methylene Blue alone; recent ones were mainly controlled trials of combinations. The authors reported that it was consistently highly effective in all endemic areas, had a strong effect on gametocytes (the parasite stage that mosquitoes pick up), and acted together with artemisinin-based combination therapy. Side effects were mild urinary and digestive symptoms and blue urine.

Trials in West African children and adults

• Burkina Faso, 2008. An open-label randomised trial in 180 children aged 6 to 10 compared Methylene Blue plus artesunate, Methylene Blue plus amodiaquine, and the local standard (artesunate plus amodiaquine). By day 28 the rate of adequate clinical and parasitological response, after correction for reinfection, was 62% with Methylene Blue plus artesunate, 82% with the standard treatment and 95% with Methylene Blue plus amodiaquine. No drug-related serious adverse events or deaths occurred; the Methylene Blue regimens were linked to mild vomiting and painful urination (Zoungrana and colleagues, 2008).
• Gametocytes, same trial. Both Methylene Blue combinations were associated with significantly fewer children carrying gametocytes on days 3, 7 and 14 than the standard combination (Coulibaly and colleagues, 2009).
• Mali, 2018. A phase 2 single-blind randomised trial in 80 males aged 5 to 50 with glucose-6-phosphate dehydrogenase-normal enzyme levels added 3 days of Methylene Blue at 15 mg/kg per day to dihydroartemisinin-piperaquine. Mosquito-feeding tests showed a median 100% fall in infectiousness to mosquitoes by day 2, compared with no meaningful change on the partner drug alone. Apart from blue urine, adverse events were similar across groups (Dicko and colleagues, 2018).

Animal work on severe malaria

In 2025 a study in rhesus monkeys infected with Plasmodium coatneyi, a model of fatal cerebral malaria, reported that Methylene Blue reversed infection-related changes in gene activity in the brainstem (Hang and colleagues, 2025). This is an animal study; it has not been tested as a treatment for cerebral malaria in people.

These trials used Methylene Blue as a partner to standard malaria drugs, in malaria-endemic regions, under trial monitoring — mainly to reduce transmission. They say nothing about cancer.

Other Parasites: Laboratory Work and Single Cases

Outside malaria, the published evidence is much thinner:

• Trypanosoma cruzi (Chagas disease). In cell culture, Methylene Blue and related dyes stopped the parasite multiplying at very low (nanomolar) concentrations, raised harmful oxygen molecules inside it and damaged its mitochondria, with low toxicity to the host cells used (Bulhões Portapilla and colleagues, 2019). No human treatment trial was found. See the Trypanosoma page.
• Leishmania (skin leishmaniasis). One 2011 report combined laboratory tests with the treatment of one patient: of two skin sores, one received Methylene Blue activated by light (photodynamic therapy) on top of a low dose of the standard antimony drug, and that sore healed faster (Song and colleagues, 2011). A single case with two lesions cannot show effectiveness. See the Leishmania page.

Searches of PubMed for Methylene Blue as a treatment for intestinal worms, tapeworms, flukes, Giardia, amoebae or Toxoplasma found mostly its old uses as a laboratory stain and in a 1950s antibody test for toxoplasmosis — not treatment trials. No clinical trial of Methylene Blue against the worm and protozoan infections the presentation discussed elsewhere was found.

Cancer Research: Photodynamic Therapy Needs Light

Most cancer research on Methylene Blue is about photodynamic therapy. In this treatment a light-sensitive drug is placed in or on a tumour and then lit with light of the colour the drug absorbs — for Methylene Blue, red light. The lit dye passes energy to oxygen, making a highly reactive form called singlet oxygen that damages cells only where dye, light and oxygen meet. Without the light, this effect does not happen. The site’s photodynamic therapy page explains the method in full.

Animal and laboratory studies

A 2023 systematic review of preclinical (animal) studies found ten that met its criteria. Seven reported smaller tumours after Methylene Blue photodynamic therapy, in models including colorectal tumour, carcinoma and melanoma; the dye doses ranged from 0.04 to 24.12 mg/kg, and nanoparticle forms worked better. The authors concluded that more research is needed (Taldaev and colleagues, 2023).

Small human reports

• A 2005 review from one research group described clinical cases treated with Methylene Blue and light, including basal cell carcinoma, Kaposi’s sarcoma and melanoma, and reported low toxicity (Tardivo and colleagues, 2005). These were case descriptions, not controlled trials.
• A 2015 prospective study without a comparison group treated 20 people with nodular or ulcerative basal cell carcinoma (the most common, slow-growing skin cancer) using a Methylene Blue gel, plus injection into larger lesions, and light every two weeks. Of the 17 who finished, 11 had a complete response over six months of follow-up (Samy and colleagues, 2015). See the site’s skin cancer page.

No randomised trial was found showing that Methylene Blue, by vein or by mouth and without targeted light, shrinks a tumour or lengthens survival in any cancer. The randomised trials found in a PubMed search for Methylene Blue and cancer were about other jobs: staining lymph nodes or tissue during surgery or endoscopy, blood pressure during surgery, delirium after surgery and mouth pain.

In Cancer Surgery and Supportive Care

The presentation spoke of using Methylene Blue on breast tumours and lymph nodes. In mainstream cancer care Methylene Blue is in fact injected near breast tumours — but as a dye for finding lymph nodes, not as a treatment. In sentinel lymph node biopsy the surgeon injects a tracer, follows it to the first lymph node draining the tumour, and removes that node to check whether the cancer has spread.

• A 2018 meta-analysis of 18 studies in breast cancer found that Methylene Blue used alone found the sentinel node 91% of the time, but missed cancer in the node in 13% of cases (the false-negative rate). The authors judged the false-negative rate too high against a US breast-surgery society’s standard and urged caution about using the dye alone (Li and colleagues, 2018).
• A 2025 report describes two women whose Methylene Blue injection under the nipple area during mastectomy with immediate implant reconstruction was followed by gangrene or skin death at the injection site (Panopoulou and Fotiou, 2025).

A separate, real supportive-care use exists. In a 2022 randomised phase 2 trial in 60 people with painful mouth sores from cancer treatment, a Methylene Blue mouth rinse for two days lowered pain scores more than usual care alone; eight people felt burning with the first dose and one stopped (Roldan and colleagues, 2022). The trial measured pain, not the cancer.

The site’s breast cancer page covers the disease itself. No published study was found of Methylene Blue applied to the skin over a breast tumour, or to lymph nodes, as a cancer treatment.

The Red-Light Combination

Methylene Blue absorbs red light strongly, and the laboratory and clinical studies cited on this page used red light of about 635 to 670 nanometres. The 616 to 680 nanometre range the speaker described is visible red light; near-infrared light lies beyond the visible range, above roughly 700 nanometres. The site’s red-light therapy page covers red light used on its own.

Two opposite uses of the same pairing

Researchers use light in two ways that pull in opposite directions. Photobiomodulation uses low-level light to stimulate cells. Photodynamic therapy adds a light-sensitive drug such as Methylene Blue to kill cells. A 2017 cell-culture study made the point: when human bone-forming cells were given a tiny amount of Methylene Blue and then 635 nm laser light, their survival fell at 72 hours and their mineral deposits fell, even at low light doses. The authors warned that unsuitable conditions may lead to undesirable results (Ateş and colleagues, 2017). In other words, Methylene Blue plus red light can harm healthy cells, not only diseased ones.

Harm from ordinary light

A 2017 report describes two patients given Methylene Blue into a vein as a tracer during parathyroid surgery who developed a blistering rash on the neck where the operating lights had shone, and one a blister on the finger under the oxygen sensor. Skin biopsies looked like skin treated with photodynamic therapy. The authors explained that the lights’ wavelengths overlap Methylene Blue’s absorption, so the dye in the skin was activated and damaged tissue (Maguire and colleagues, 2017).

Human studies of the combination

The human data on Methylene Blue with red light outside photodynamic treatment of a lesion are very small. A 2022 pilot study treated eight people with COVID-19 in the Bahamas with Methylene Blue and 660 nm light in the nose and mouth, plus oral Methylene Blue and/or light therapy; it had no comparison group, and the paper states that its medical director had filed a patent on the protocol (Hepburn and colleagues, 2022). No study was found of Methylene Blue combined with red light in people with breast cancer, or of any “synergistic” benefit for cancer outcomes.

Vein, Mouth or Skin: What Happens in the Body

Several of the speaker’s descriptions of how the body handles Methylene Blue match the published data:

• Liver and urine. The US label states that Methylene Blue is extensively broken down in the liver, that about 40% is passed unchanged in the urine and that its half-life is about 24 hours. The label lists coloured urine (chromaturia) among the commonest reactions, and blue staining of urine, skin and mucous membranes (U.S. Food and Drug Administration label, 2023).
• By vein versus by mouth. In a 2000 study in seven volunteers given 100 mg, the amount in the blood over time after an oral dose was a small fraction of that after the same dose by vein. In rats, the gut route gave higher levels in the intestinal wall and liver but lower levels in blood and brain than the vein route (Peter and colleagues, 2000). An oral dose is therefore not the same exposure as an intravenous one.
• Brain. Methylene Blue does reach the brain: the rat data above show it, and the U.S. Food and Drug Administration’s serotonin warnings (below) concern reactions in the central nervous system. That same brain access is what makes the serotonin interaction dangerous.

No pharmacokinetic study of Methylene Blue placed under the tongue, or spread on skin over a tumour, was found in this review. Grades differ too: the dye sold by chemical suppliers is not made to medicine standards — see the pharmaceutical grade versus industrial dye page.

Is It “Non-Toxic”? What the Label Records

At the doses used in trials, many people tolerate Methylene Blue well, and the malaria trials above reported mostly mild effects. But the US label does not describe it as non-toxic. It records:

• Common effects. In 82 healthy adults given a single 2 mg/kg dose by vein, the reactions reported in more than 10% were pain in an arm or leg, coloured urine, altered taste, feeling hot, dizziness, heavy sweating, nausea, skin discoloration and headache. One serious reaction occurred: fainting with pauses in the heartbeat of 3 to 14 seconds.
• Large doses. Low blood pressure, wheezing and lower oxygen levels were reported after single doses of 3 mg/kg or more. Cumulative doses of 7 mg/kg or more caused chest pain, breathlessness, fast heartbeat, tremor, confusion, mild methemoglobinemia (up to 7%) and heart-tracing changes. A single dose of 20 mg/kg or more caused severe breakdown of red blood cells, jaundice and death.
• Boxed warning and contraindication. The label carries a boxed warning for serotonin syndrome and lists glucose-6-phosphate dehydrogenase deficiency as a contraindication (both below). It also states that the dye can interfere with pulse oximeter readings.

Add to these the skin death after injection and the light-triggered skin injury described earlier. The speaker’s list of side effects — dizziness, nausea, headache — matches part of the label; the words “harmless” and “non-toxic” do not match the label’s overdose and warning sections. Doses on the label and in trials are set out on the site’s dosing page.

Glucose-6-Phosphate Dehydrogenase Deficiency: How Common Is It?

Glucose-6-phosphate dehydrogenase is an enzyme that lets red blood cells make reduced nicotinamide adenine dinucleotide phosphate (NADPH), a molecule that protects them from oxidative damage. Methylene Blue needs reduced nicotinamide adenine dinucleotide phosphate inside red cells to be converted to its active form, so in glucose-6-phosphate dehydrogenase deficiency it works less well and can itself damage red cells. The speaker was right that glucose-6-phosphate dehydrogenase deficiency matters; the published figures do not support calling it very rare.

How common it is

• The World Health Organization’s Global Malaria Programme states that glucose-6-phosphate dehydrogenase deficiency affects more than 400 million people worldwide (World Health Organization). That is roughly one person in twenty alive today — about fifty times the one-in-a-thousand figure given in the presentation.
• A 2012 mapping study built from 1,734 community surveys estimated the highest prevalence, peaking at 32.5%, across sub-Saharan Africa and the Arabian Peninsula, and a deficiency gene frequency of about 8% across malaria-endemic countries; most affected people lived in Asia (Howes and colleagues, 2012).

How often a particular clinic sees it depends on its patients’ ancestry; the presentation did not say how its figure was measured. The gene sits on the X chromosome (Howes and colleagues, 2012), so full deficiency is most common in males.

What Methylene Blue does in Glucose-6-Phosphate Dehydrogenase deficiency

• The US label contraindicates Methylene Blue in glucose-6-phosphate dehydrogenase deficiency because of the risk of haemolytic anaemia, stating that treatment may cause severe haemolysis and severe anaemia, and that it may not work in these patients (U.S. Food and Drug Administration label, 2023).
• A 2010 evidence-based review of medicines in glucose-6-phosphate dehydrogenase deficiency found solid evidence against only seven drugs then in use, and Methylene Blue was one of them, alongside dapsone, nitrofurantoin, phenazopyridine, primaquine, rasburicase and toluidine blue (Youngster and colleagues, 2010).
• In pooled data from four West African trials (1,005 children with malaria, 199 of them glucose-6-phosphate dehydrogenase-deficient), Methylene Blue at 15 mg/kg per day lowered haemoglobin significantly in children with the full deficiency, to a lowest value of 8.5 g/dL; two episodes of haemolysis occurred, both in children who had received Methylene Blue. The authors judged the effect of limited clinical relevance in that setting but needing monitoring (Müller and colleagues, 2013).

The speaker’s remark about vitamin C in glucose-6-phosphate dehydrogenase deficiency is covered on the site’s high-dose intravenous vitamin C page. The enzyme and its testing are explained on the methemoglobinemia and glucose-6-phosphate dehydrogenase page, the glucose-6-phosphate dehydrogenase deficiency page and the glucose-6-phosphate dehydrogenase test page.

Serotonin Syndrome: Not Only Monoamine Oxidase Inhibitors

Methylene Blue is itself a strong, reversible monoamine oxidase inhibitor: it blocks monoamine oxidase A, an enzyme that breaks down serotonin. Combined with other medicines that raise serotonin, it can cause serotonin syndrome — confusion, agitation, muscle twitching, sweating, shivering, fever and, in severe cases, seizures or coma. The presentation named only monoamine-oxidase-inhibitor antidepressants. The U.S. Food and Drug Administration’s warnings are broader.

• U.S. Food and Drug Administration, 26 July 2011. The U.S. Food and Drug Administration reported serious central nervous system reactions in people taking serotonergic psychiatric medicines who were given Methylene Blue, noted that health professionals and patients may not realise it has monoamine-oxidase-inhibitor properties, and stated that it “should generally not be given to patients taking serotonergic drugs”, with exceptions for life-threatening emergencies (U.S. Food and Drug Administration, July 2011).
• U.S. Food and Drug Administration, 20 October 2011. The update stated that the reported cases occurred in people taking a selective serotonin reuptake inhibitor (such as paroxetine, fluoxetine, sertraline, citalopram or escitalopram), a serotonin-norepinephrine reuptake inhibitor (venlafaxine, desvenlafaxine, duloxetine) or clomipramine. The monoamine oxidase inhibitors, other tricyclics, bupropion, buspirone, mirtazapine and trazodone were placed in a second group whose risk was unclear. Most cases followed intravenous doses of 1 to 8 mg/kg during parathyroid surgery, and the U.S. Food and Drug Administration said the risk by mouth, by local tissue injection or below 1 mg/kg was not known (U.S. Food and Drug Administration, October 2011).
• The current label. The boxed warning states that Methylene Blue may cause serious or fatal serotonin syndrome with serotonergic drugs and opioids, and that use with selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, monoamine oxidase inhibitors and opioids is to be avoided (U.S. Food and Drug Administration label, 2023).
• Case reviews. A 2010 systematic review found 26 patients who developed acute confusion after a Methylene Blue infusion; 24 were taking a serotonin reuptake inhibitor and one clomipramine, and serotonin syndrome was a possible diagnosis in all 25 (Ng and Cameron, 2010).

Commonly prescribed antidepressants, rather than the older monoamine oxidase inhibitors, account for nearly all the reported cases. Opioid pain medicines, often used by people with cancer, are named in the boxed warning too. The full drug lists are on the site’s drug interactions and serotonin syndrome page. Decisions about cancer treatment and antiparasitic medicines belong with a clinician.

How the Claim Compares With the Research

Supported

• Antiparasitic against malaria. Randomised trials in Africa report that Methylene Blue, as a partner to standard drugs, clears malaria parasites and sharply cuts transmission to mosquitoes.
• Liver breakdown, urinary excretion, blue or green-tinted urine. The label records all three.
• Reaches the brain. Animal distribution data and the U.S. Food and Drug Administration’s central-nervous-system warnings support this.
• Glucose-6-phosphate dehydrogenase deficiency is a reason not to give it. The label lists it as a contraindication.
• Dizziness, nausea and headache as side effects. All appear on the label.

Supported only in part

• Broad antiparasitic action. Beyond malaria, the evidence is cell-culture work on Trypanosoma cruzi and one patient with skin leishmaniasis treated with light. No trial against intestinal worms or the other parasites the presentation discussed was found.
• Cancer. Methylene Blue photodynamic therapy shrank tumours in animal studies and in small uncontrolled human series of skin cancers — but only when the dye was activated by light at the tumour. Its established cancer-care roles are as a lymph-node dye and, in one trial, a mouth rinse for treatment-related pain.
• Used on breast tumours and lymph nodes. Surgeons do inject it near breast tumours to map lymph nodes, a diagnostic step with a known miss rate and occasional skin death; no study of it as a topical treatment of breast tumours was found.
• The second caution. Monoamine oxidase inhibitors are on the label’s list, but the U.S. Food and Drug Administration’s reported cases involved mainly selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors and clomipramine, and the boxed warning also names opioids.

Contradicted by published data

• “Harmless” and “non-toxic”. The label carries a boxed warning for possibly fatal serotonin syndrome, a contraindication for glucose-6-phosphate dehydrogenase deficiency, and an overdose section that includes death after very large doses. Case reports describe skin death and light-triggered skin injury.
• Glucose-6-phosphate dehydrogenase deficiency in about one in a thousand. World Health Organization puts the number affected at more than 400 million people, roughly one in twenty worldwide, with prevalence above 30% in parts of Africa and the Arabian Peninsula.
• 616 to 680 nanometres as near-infrared. That range is visible red light.

No research found

• A “synergistic” benefit of Methylene Blue and red light for people with breast or any other cancer — the combination is known chiefly as a way of killing cells, including healthy ones.
• Methylene Blue given under the tongue or on skin over a tumour as a cancer treatment.
• Any trial linking Methylene Blue to survival or tumour response in cancer without targeted light.

What Is Not Known

• Whether Methylene Blue photodynamic therapy works as well as, or better than, established treatments for any cancer: the human data are small, uncontrolled and come mostly from a few research groups.
• Whether Methylene Blue has any effect on intestinal worms, flukes, tapeworms or protozoa in people.
• The risk of serotonin syndrome at the low oral doses sold for self-use, or by routes other than a vein; the U.S. Food and Drug Administration said in 2011 that this was not known.
• The risk of haemolysis from repeated low oral doses in people with glucose-6-phosphate dehydrogenase deficiency: the pooled West African data concern the African A− variant and short malaria courses, while the 2012 mapping study rated the variants found in Asia as carrying the highest relative risk of haemolysis.
• What happens when Methylene Blue in the skin meets home red-light devices, daylight or other strong light over many weeks.
• Whether taking Methylene Blue during chemotherapy or radiotherapy changes how well those treatments work.

Connections

• Cancer and Parasites
• Ivermectin in Cancer Research
• Artemisinin and Artesunate in Cancer Research
• Mebendazole, Fenbendazole and Albendazole in Cancer Research
• Malaria and Burkitt Lymphoma
• Methylene Blue
• Methylene Blue Drug Interactions and Serotonin Syndrome
• Methylene Blue, Methemoglobinemia and Glucose-6-Phosphate Dehydrogenase Deficiency
• Methylene Blue Photodynamic Therapy and Cancer Research
• Methylene Blue History: Ehrlich and the Phenothiazines
• Red-Light Therapy
• Malaria
• Trypanosoma
• Leishmania
• Glucose-6-Phosphate Dehydrogenase Deficiency
• Glucose-6-Phosphate Dehydrogenase Deficiency Test

Key Research Papers

1. Lu G, Nagbanshi M, Goldau N, et al. Efficacy and safety of methylene blue in the treatment of malaria: a systematic review. BMC Medicine. 2018;16(1):59. PubMed PMID: 29690878
2. Zoungrana A, Coulibaly B, Sié A, et al. Safety and efficacy of methylene blue combined with artesunate or amodiaquine for uncomplicated falciparum malaria: a randomized controlled trial from Burkina Faso. PLoS One. 2008;3(2):e1630. PubMed PMID: 18286187
3. Coulibaly B, Zoungrana A, Mockenhaupt FP, et al. Strong gametocytocidal effect of methylene blue-based combination therapy against falciparum malaria: a randomised controlled trial. PLoS One. 2009;4(5):e5318. PubMed PMID: 19415120
4. Dicko A, Roh ME, Diawara H, et al. Efficacy and safety of primaquine and methylene blue for prevention of Plasmodium falciparum transmission in Mali: a phase 2, single-blind, randomised controlled trial. The Lancet Infectious Diseases. 2018;18(6):627-639. PubMed PMID: 29422384
5. Hang JW, Leong YW, Narang V, et al. Methylene blue treatment of fatal cerebral malaria and identification of potential blood biomarkers. Nature Communications. 2025;16(1):10534. PubMed PMID: 41298347
6. Bulhões Portapilla G, Pereira LM, Bronzon da Costa CM, et al. Phenothiazinium Dyes Are Active against Trypanosoma cruzi In Vitro. BioMed Research International. 2019;2019:8301569. PubMed PMID: 31355283
7. Song D, Lindoso JA, Oyafuso LK, et al. Photodynamic therapy using methylene blue to treat cutaneous leishmaniasis. Photomedicine and Laser Surgery. 2011;29(10):711-5. PubMed PMID: 21671755
8. Taldaev A, Terekhov R, Nikitin I, et al. Methylene blue in anticancer photodynamic therapy: systematic review of preclinical studies. Frontiers in Pharmacology. 2023;14:1264961. PubMed PMID: 37841915
9. Tardivo JP, Del Giglio A, de Oliveira CS, et al. Methylene blue in photodynamic therapy: From basic mechanisms to clinical applications. Photodiagnosis and Photodynamic Therapy. 2005;2(3):175-91. PubMed PMID: 25048768
10. Samy NA, Salah MM, Ali MF, Sadek AM. Effect of methylene blue-mediated photodynamic therapy for treatment of basal cell carcinoma. Lasers in Medical Science. 2015;30(1):109-15. PubMed PMID: 25030404
11. Li J, Chen X, Qi M, Li Y. Sentinel lymph node biopsy mapped with methylene blue dye alone in patients with breast cancer: A systematic review and meta-analysis. PLoS One. 2018;13(9):e0204364. PubMed PMID: 30235340
12. Panopoulou G, Fotiou A. Skin Necrosis After Methylene Blue Dye Use in Immediate Breast Reconstruction. Plastic and Reconstructive Surgery Global Open. 2025;13(2):e6515. PubMed PMID: 39925476
13. Roldan CJ, Huh B, Song J, et al. Methylene blue for intractable pain from oral mucositis related to cancer treatment: a randomized phase 2 clinical trial. BMC Medicine. 2022;20(1):377. PubMed PMID: 36324139
14. Ateş GB, Ak A, Garipcan B, Gülsoy M. Methylene blue mediated photobiomodulation on human osteoblast cells. Lasers in Medical Science. 2017;32(8):1847-1855. PubMed PMID: 28776111
15. Maguire CA, Sharma A, Alarcon L, et al. Histological Features of Methylene Blue-Induced Phototoxicity Administered in the Context of Parathyroid Surgery. The American Journal of Dermatopathology. 2017;39(8):e110-e115. PubMed PMID: 28398918
16. Hepburn J, Williams-Lockhart S, Bensadoun RJ, Hanna R. A Novel Approach of Combining Methylene Blue Photodynamic Inactivation, Photobiomodulation and Oral Ingested Methylene Blue in COVID-19 Management: A Pilot Clinical Study with 12-Month Follow-Up. Antioxidants (Basel). 2022;11(11):2211. PubMed PMID: 36358582
17. Peter C, Hongwan D, Küpfer A, Lauterburg BH. Pharmacokinetics and organ distribution of intravenous and oral methylene blue. European Journal of Clinical Pharmacology. 2000;56(3):247-50. PubMed PMID: 10952480
18. Howes RE, Piel FB, Patil AP, et al. G6PD deficiency prevalence and estimates of affected populations in malaria endemic countries: a geostatistical model-based map. PLoS Medicine. 2012;9(11):e1001339. PubMed PMID: 23152723
19. Youngster I, Arcavi L, Schechmaster R, et al. Medications and glucose-6-phosphate dehydrogenase deficiency: an evidence-based review. Drug Safety. 2010;33(9):713-26. PubMed PMID: 20701405
20. Müller O, Mockenhaupt FP, Marks B, et al. Haemolysis risk in methylene blue treatment of G6PD-sufficient and G6PD-deficient West-African children with uncomplicated falciparum malaria: a synopsis of four RCTs. Pharmacoepidemiology and Drug Safety. 2013;22(4):376-85. PubMed PMID: 23135803
21. Ng BK, Cameron AJ. The role of methylene blue in serotonin syndrome: a systematic review. Psychosomatics. 2010;51(3):194-200. PubMed PMID: 20484716

PubMed Topic Searches

1. Methylene Blue in malaria: randomised trials
2. Methylene Blue photodynamic therapy in cancer
3. Methylene Blue and serotonin syndrome
4. Methylene Blue and G6PD deficiency

Other Sources

1. U.S. Food and Drug Administration. FDA Drug Safety Communication: Serious CNS reactions possible when methylene blue is given to patients taking certain psychiatric medications. 26 July 2011 (archived copy of the FDA page). fda.gov (archived)
2. U.S. Food and Drug Administration. FDA Drug Safety Communication: Updated information about the drug interaction between methylene blue (methylthioninium chloride) and serotonergic psychiatric medications. 20 October 2011 (archived copy of the FDA page). fda.gov (archived)
3. U.S. Food and Drug Administration. Methylene Blue injection, prescribing information (revised 2023). accessdata.fda.gov
4. World Health Organization, Global Malaria Programme. G6PD rapid diagnostic tests. who.int

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