Mastic Gum (Pistacia lentiscus)
Table of Contents
- Overview
- Traditional Use: The Mastic of Chios
- Active Compounds
- H. Pylori: The Famous Claim, Examined
- Functional Dyspepsia and Stomach Comfort
- Oral Health and Dental Plaque
- Cholesterol and Liver Markers
- Crohn's Disease: Pilot Evidence Only
- Forms and Preparations
- Dosage
- Cautions and Contraindications
- Research Papers and References
Overview
Mastic gum is the dried resin of the mastic tree, Pistacia lentiscus — a slow-growing, drought-hardy evergreen shrub of the cashew family (Anacardiaceae) that rarely stands taller than a person. When the bark of the cultivated variety is scored in summer, the tree "weeps": droplets of clear, sticky sap ooze from the cuts, hang from the trunk, and slowly harden in the sun into translucent, glassy droplets. Because of their shape, the hardened pieces have been called "tears" of mastic for over two thousand years, and the harvest is still described on Chios as gathering the tears of the tree.
A fresh tear is brittle and shatters like amber candy. Chewed, it behaves unlike any other resin: after a first bite that is bitter and pine-like, it softens into a cohesive, opaque white gum with a clean cedar-and-pine flavor. This is the original chewing gum of the Mediterranean world — the Greek verb mastichein, "to gnash the teeth," gave the resin its name, and it is the same root that gives English the word masticate.
Today mastic leads three parallel lives: as a food (it flavors Greek and Middle Eastern sweets, breads, liqueurs, and ice creams), as a chewing gum for breath and teeth, and as a dietary supplement taken mainly for the stomach. The supplement use exploded after a 1998 letter in the New England Journal of Medicine reported that mastic killed Helicobacter pylori — the ulcer-causing stomach bacterium — in the laboratory. That finding is real, but the human story that followed is considerably more modest than most supplement marketing admits, and this article lays it out honestly, study by study.
Traditional Use: The Mastic of Chios
Pistacia lentiscus grows wild all around the Mediterranean, from Spain to the Levant, but commercial-quality mastic comes almost entirely from one small place: the southern third of the Greek island of Chios, a few miles off the Turkish coast. Only there does the cultivated variety, Pistacia lentiscus var. Chia, reliably yield abundant resin of chewable quality — a quirk of subspecies and microclimate that centuries of attempted transplantation elsewhere have never fully reproduced. The two dozen medieval villages that grow it are known collectively as the Mastichochoria, the "mastic villages."
The harvest is a craft in its own right. In early summer, growers sweep and level the ground beneath each tree and spread a layer of white calcium-carbonate powder so falling droplets stay clean. From June to September they make shallow cuts (kentos) in the bark with a pointed tool; the tears that form are gathered, washed, sorted by size, and cleaned piece by piece — largely by hand, largely by the village women, exactly as it has been done for generations. The European Union protects "Masticha Chiou" (Chios Mastiha) as a Protected Designation of Origin product, and in 2014 UNESCO inscribed the know-how of mastic cultivation on Chios on its Representative List of the Intangible Cultural Heritage of Humanity.
The medicinal tradition is genuinely ancient, and it centers on the stomach and the mouth. Dioscorides, the first-century Greek physician whose De Materia Medica shaped European pharmacy for 1,500 years, recommended mastic for stomach complaints and indigestion and noted its use for sweetening the breath; Galen likewise listed mastic among remedies for inflammation of the stomach and digestive troubles. Those citations tell us the tradition is old and consistent — they are historical testimony, not clinical evidence, and ancient endorsement is never proof that a remedy works. It is striking, though, that the modern research agenda (ulcers, dyspepsia, oral bacteria) is almost exactly the ancient indication list.
Mastic's economic history reads like a thriller. The Genoese, who ruled Chios from 1346 to 1566, ran the mastic trade as a fortified monopoly through the Giustiniani family's trading company, and laid out the Mastichochoria as walled labyrinths against pirate raids. Under the Ottomans, who took the island in 1566, mastic became one of the empire's most jealously guarded luxuries: the villages enjoyed special tax privileges in exchange for tribute paid in resin, smuggling was severely punished, and the tears were prized in the Sultan's court — famously chewed in the harem as breath freshener and used in palace confectionery. The crop was valuable enough that during the notorious 1822 massacre of Chios the mastic-growing villages were at first spared destruction. Mastic remains the economic backbone of southern Chios today, marketed through a growers' cooperative founded in 1938.
Active Compounds
Chemically, mastic resin is a dense package of triterpenes — six-ring plant molecules built from the same backbone family as plant sterols — held together by a natural polymer that gives the gum its chew. The main constituents:
- Triterpenic acids — the fraction believed to carry most of the biological activity. The two signature molecules, found in few other plants, are masticadienonic acid and isomasticadienonic acid; they are accompanied by related acids such as masticadienolic and isomasticadienolic acid, oleanonic acid, and moronic acid. In laboratory work on H. pylori, the acid fraction was the most bactericidal part of the resin, with isomasticadienolic acid the most active single constituent tested.
- Neutral triterpenoids — alcohols and ketones such as tirucallol and beta-amyrin-type compounds, with milder activity in the same assays.
- cis-1,4-poly-β-myrcene — a natural insoluble polymer making up roughly a quarter of the raw resin. It is what turns a brittle tear into an elastic gum, but it is biologically inert baggage: it dissolves poorly, can trap the active triterpenes, and researchers who removed it (the "total mastic extract without polymer" used in the Paraschos studies) found the polymer-free extract easier to work with and more active gram-for-gram. This detail matters when comparing raw-gum studies to extract studies.
- Volatile fraction (mastic essential oil) — a few percent of the resin, dominated by alpha-pinene and beta-myrcene with smaller amounts of limonene and linalool. This is the source of the pine-cedar aroma and contributes antimicrobial activity in its own right; it is also sold separately as mastic oil for flavoring.
No single "mastic molecule" explains the resin's effects; the research picture is of a family of triterpenic acids with modest antibacterial and anti-inflammatory activity, delivered in a slow-release chewable matrix.
H. Pylori: The Famous Claim, Examined
Evidence tier: Preliminary / limited human evidence. Strong laboratory activity, partial suppression in small human pilots, and clearly inferior to standard antibiotic therapy for eradication. This section exists because the claim is everywhere and deserves an honest accounting.
Helicobacter pylori is the spiral bacterium that colonizes the stomach lining of roughly half of humanity and is the main cause of peptic ulcers and a major risk factor for stomach cancer. In December 1998, Huwez and colleagues published a short letter in the New England Journal of Medicine titled, memorably, "Mastic Gum Kills Helicobacter pylori". They reported that mastic killed cultured H. pylori at low concentrations — bactericidal activity at concentrations as low as roughly 0.06 mg/mL — and connected this to mastic's long folk reputation for stomach ulcers. The letter became one of the most-quoted items in the herbal literature, and it is the reason nearly every mastic supplement bottle mentions H. pylori.
What the letter showed was real in-vitro activity. What it could not show was that chewing or swallowing mastic clears the infection from a living stomach — and the follow-up work is where the story gets honest:
- Mice, 2003 (negative). Loughlin and colleagues gave mastic as monotherapy to H. pylori-infected mice and reported bluntly, in the paper's own title, that monotherapy with mastic does not eradicate the infection.
- Humans, 2003 (negative). Bebb and colleagues gave a small group of infected patients 1 g of mastic four times daily for two weeks and found no measurable effect on bacterial load by urea breath test.
- The mechanism paper, 2007 (partial rescue). Paraschos and colleagues showed why the crude gum may fail: the insoluble polymer. Using a polymer-free mastic extract, they confirmed genuine bactericidal activity in vitro (the triterpenic-acid fraction was the most potent part) and, in infected mice treated for three months, achieved roughly a thirty-fold reduction in stomach colonization — suppression, but still not eradication.
- The human pilot trial, 2010 (partial activity, far below antibiotics). Dabos and colleagues randomized 52 infected patients: pure mastic at 350 mg three times daily or 1.05 g three times daily for 14 days, mastic plus the acid-blocker pantoprazole, or standard triple therapy (pantoprazole plus amoxicillin plus clarithromycin). Confirmed eradication: about 31% and 38% in the two mastic-alone arms, none in the mastic-plus-pantoprazole arm, and about 77% with antibiotic triple therapy.
The fair summary: mastic has genuine anti-H. pylori activity and, as monotherapy, appears to clear the infection in perhaps a third of people in small short pilots — a rate no gastroenterologist would accept, since eradication regimens are expected to succeed in well over 80–90% of patients. Untreated or half-treated H. pylori is not a neutral outcome: it drives ulcers and stomach-cancer risk, and partial suppression can also make the infection harder to detect on breath and stool tests without actually curing it. Mastic is not a substitute for antibiotic eradication therapy when treatment is indicated. Whether it has value as an add-on to antibiotics, or as a gentle suppressive option for people who cannot take antibiotics, are reasonable open questions that the trials to answer them have simply not been run at scale.
Functional Dyspepsia and Stomach Comfort
Evidence tier: Moderate-but-thin — one well-designed placebo-controlled trial.
Functional dyspepsia — recurring upper-stomach pain, burning, and uncomfortable fullness with no ulcer or other visible cause on endoscopy — is exactly the complaint mastic was chewed for on Chios for centuries, and it is where the human evidence is most respectable. In a prospective, randomized, double-blind trial published in 2010, Dabos and colleagues assigned just under 150 patients meeting formal (Rome II) criteria for functional dyspepsia to 350 mg of pure Chios mastic three times daily or matching placebo for three weeks.
The result favored mastic clearly: 77% of the mastic group reported improvement in symptoms versus 40% on placebo, with significant advantages on a validated dyspepsia severity score and on individual symptoms including general stomach pain, stomach pain when anxious, and dull upper-abdominal ache. Tolerability was comparable to placebo.
The honest caveats: it is one trial, it was short (three weeks), and functional dyspepsia is a condition with a famously high placebo response — visible in the 40% placebo improvement here. A single positive RCT makes mastic a reasonable, low-risk thing to try for garden-variety indigestion; it does not make it an established therapy. Note also that this trial was about dyspepsia, not acid reflux: mastic has no meaningful trial evidence in GERD, where the problem is a leaky valve rather than the stomach lining, so its frequent marketing for reflux outruns the data.
Oral Health and Dental Plaque
Evidence tier: Preliminary — small chewing studies with surrogate endpoints.
Mastic's oldest continuous use is as a chewing gum for clean breath and teeth, and small modern studies support the direction of the tradition without proving dental outcomes:
- A pilot study in the Journal of Periodontology (2003) had volunteers chew mastic gum versus a placebo gum and found significantly less new dental-plaque accumulation and lower bacterial counts in saliva with mastic over the study period.
- A 2006 study in Archives of Oral Biology found mastic gum inhibited Streptococcus mutans — the main cavity-forming bacterium — in the laboratory, and that chewing it reduced mutans streptococci counts in saliva in volunteers.
What is missing is the endpoint that matters: no trial has shown that mastic chewing actually reduces cavities or gum disease over months and years. The honest read is that mastic is at least as good as, and possibly modestly better than, ordinary sugar-free gum for plaque-related measures — and mechanical chewing plus saliva flow is itself much of the benefit of any gum. As a pleasant, sugar-free traditional gum with mild antibacterial activity, it is a sensible habit; as a treatment for periodontal disease it is unproven. See the site's Oral Microbiome page for the wider picture into which this fits.
Cholesterol and Liver Markers
Evidence tier: Preliminary — one uncontrolled long-term study plus one small placebo-controlled pilot.
Two Greek studies — both, fittingly, involving Chios — suggest metabolic effects that are interesting but nowhere near established:
- Triantafyllou and colleagues (2007) followed 133 healthy volunteers taking mastic for 18 months, the longest human exposure on record. The high-dose group (about 5 g of mastic powder daily) showed reductions in total cholesterol and in the liver enzymes ALT, AST, and GGT. The critical weakness: there was no placebo group, so drift, diet, and regression to the mean cannot be excluded. Its most useful finding may simply be that 5 g/day for 18 months was well tolerated.
- The CHIOS-MASTIHA pilot (2016), a prospective randomized placebo-controlled study in about 150 healthy volunteers published in the European Journal of Preventive Cardiology, reported modest reductions in total cholesterol and blood glucose versus placebo, with the authors noting the clearest signal in overweight participants.
Taken together these justify larger trials, not health claims. Nobody with high cholesterol or fatty liver should choose mastic over interventions with outcome evidence (diet pattern, exercise, and where indicated, medication); at most, mastic is a traditional food ingredient with a plausible modest metabolic bonus.
Crohn's Disease: Pilot Evidence Only
Evidence tier: Pilot only — a tiny uncontrolled study; not a treatment.
One small Greek study (Kaliora and colleagues, 2007) gave ten patients with mildly-to-moderately active Crohn's disease about 2.2 g of mastic daily (six 0.37 g capsules) for four weeks. Disease-activity scores fell significantly, as did the inflammatory markers C-reactive protein and interleukin-6. That is genuinely intriguing for a resin — but ten patients, four weeks, and no placebo group is hypothesis-generating research, full stop. Crohn's is a serious, relapsing disease where undertreatment causes permanent bowel damage; mastic belongs, at most, in the "discuss with your gastroenterologist as a food-grade extra" category, never as a replacement for maintenance therapy. Nearly two decades later, the follow-up trial has not appeared — which is itself informative.
Forms and Preparations
- Raw tears (for chewing) — the traditional form: sun-dried resin droplets sold by size, from large tears down to small "pittas." Start with a piece or two; the first minute is brittle and bitter before it gathers into a smooth white gum that keeps its texture for an hour or more. This is the form for breath and oral-health use, and the one to buy if you want genuine PDO Chios mastiha (look for the cooperative's sealed tins).
- Capsules of ground resin — the form used in most clinical trials, typically 250–500 mg of pure mastic powder per capsule. Ground mastic is simply the tears pulverized; "extract" products vary more in what they contain.
- Powder — ground tears sold loose, used both as a supplement and as a spice in Greek and Middle Eastern baking (tsoureki, ma'amoul, Ramadan sweets, mastic ice cream). It dissolves poorly in water — the resin is hydrophobic — so it is usually pounded with sugar and folded into food.
- Mastic oil — the distilled essential oil, used in drops for flavoring. It is far more concentrated than the resin and is a flavoring, not a supplement format for self-dosing.
- Traditional foods and drinks — mastiha liqueur, "submarine" vanilla-mastic spoon sweets, mastic water for pastry. Pleasant, but the doses involved are culinary, not clinical.
- Toothpastes and mouthwashes with mastic exist, mostly from Greek producers; they have little independent evidence beyond the chewing studies above.
A sourcing note: genuine Chios mastic commands a high price, and cheaper aromatic resins (frankincense/olibanum, pine rosin, or unrelated "gum" products) are sometimes sold under the mastic name in international markets. The clinical studies above used real Chios mastiha; buy PDO-labeled resin or reputable standardized capsules.
Dosage
There is no official recommended intake; the honest anchor is what the human studies actually used:
- Functional dyspepsia: 350 mg three times daily (about 1 g/day) for 3 weeks — the placebo-controlled trial dose.
- H. pylori pilots: 350 mg to 1.05 g three times daily (about 1–3 g/day) for 14 days — and even the high dose eradicated the infection in only a minority.
- Crohn's pilot: about 2.2 g/day in divided capsules for 4 weeks.
- Long-term metabolic study: up to 5 g/day of powder for 18 months, mainly notable for tolerability.
In practice, supplement regimens of roughly 1 to 2.8 g of resin per day in two or three divided doses, often taken before meals on an emptier stomach, cover the range most trials used. For chewing, one or two tears as desired — the swallowed dose from chewing is small and unstandardized. More is not demonstrably better: the dyspepsia benefit appeared at 1 g/day, and tripling the dose in the H. pylori pilot barely moved eradication.
Cautions and Contraindications
- Tree-nut-adjacent allergy caution. The mastic tree is Pistacia lentiscus — the same genus as the pistachio and the same family (Anacardiaceae) as cashew, mango, and sumac. Anyone with a pistachio or cashew allergy should treat mastic as potentially cross-reactive and avoid it or clear it with an allergist first; contact-type allergic reactions to the resin have also been reported.
- Generally well tolerated. Across the trials above — up to 5 g/day and up to 18 months — reported side effects were sparse and mild, mostly occasional digestive upset; the dyspepsia trial saw adverse events comparable to placebo. Long-term safety beyond 18 months is simply undocumented.
- Pregnancy and breastfeeding: no data. There are no safety studies of supplemental mastic in pregnancy or lactation; culinary amounts in food are one thing, gram-level daily dosing is another and is best avoided.
- Do not use it in place of H. pylori treatment. If you have a proven H. pylori infection with an ulcer, a strong family history of stomach cancer, or any indication your doctor considers treatment-worthy, take the eradication regimen — the pilot data above show mastic alone fails most people, and partial suppression can muddy follow-up breath and stool testing.
- Jaw and dental work. Mastic is a firm, long-lasting chew; people with TMJ problems or fragile dental restorations should favor capsules over hours of chewing.
- Quality. Adulterated or mislabeled "mastic" products exist outside Greece; buy PDO Chios resin or reputable brands (see Forms above).
Research Papers and References
Key peer-reviewed papers on mastic gum. Author, title, and journal are given in plain text; the linked portion opens the paper's DOI record.
- Huwez FU, Thirlwell D, Cockayne A, Ala'Aldeen DA. Mastic gum kills Helicobacter pylori. New England Journal of Medicine. 1998;339(26):1946 — the famous in-vitro letter that launched modern interest.
- Loughlin MF, Ala'Aldeen DA, Jenks PJ. Monotherapy with mastic does not eradicate Helicobacter pylori infection from mice. Journal of Antimicrobial Chemotherapy. 2003;51(2):367–371.
- Bebb JR, Bailey-Flitter N, Ala'Aldeen D, Atherton JC. Mastic gum has no effect on Helicobacter pylori load in vivo. Journal of Antimicrobial Chemotherapy. 2003;52(3):522–523 — small negative human study.
- Paraschos S, Magiatis P, Mitakou S, et al. In vitro and in vivo activities of Chios mastic gum extracts and constituents against Helicobacter pylori. Antimicrobial Agents and Chemotherapy. 2007;51(2):551–559 — identifies the triterpenic-acid fraction and the polymer problem.
- Dabos KJ, Sfika E, Vlatta LJ, Giannikopoulos G. The effect of mastic gum on Helicobacter pylori: a randomized pilot study. Phytomedicine. 2010;17(3–4):296–299 — ~31–38% eradication with mastic alone versus ~77% with triple therapy.
- Dabos KJ, Sfika E, Vlatta LJ, Frantzi D, Amygdalos GI, Giannikopoulos G. Is Chios mastic gum effective in the treatment of functional dyspepsia? A prospective randomised double-blind placebo controlled trial. Journal of Ethnopharmacology. 2010;127(2):205–209.
- Takahashi K, Fukazawa M, Motohira H, Ochiai K, Nishikawa H, Miyata T. A pilot study on antiplaque effects of mastic chewing gum in the oral cavity. Journal of Periodontology. 2003;74(4):501–505.
- Aksoy A, Duran N, Koksal F. In vitro and in vivo antimicrobial effects of mastic chewing gum against Streptococcus mutans and mutans streptococci. Archives of Oral Biology. 2006;51(6):476–481.
- Triantafyllou A, Chaviaras N, Sergentanis TN, Protopapa E, Tsaknis J. Chios mastic gum modulates serum biochemical parameters in a human population. Journal of Ethnopharmacology. 2007;111(1):43–49 — 18-month uncontrolled study.
- Kartalis A, Didagelos M, Georgiadis I, et al. Effects of Chios mastic gum on cholesterol and glucose levels of healthy volunteers: a prospective, randomized, placebo-controlled, pilot study (CHIOS-MASTIHA). European Journal of Preventive Cardiology. 2016;23(7).
- Kaliora AC, Stathopoulou MG, Triantafillidis JK, Dedoussis GV, Andrikopoulos NK. Chios mastic treatment of patients with active Crohn's disease. World Journal of Gastroenterology. 2007;13(5):748–753 — the 10-patient uncontrolled pilot.
- Pachi VK, Mikropoulou EV, Gkiouvetidis P, et al. Traditional uses, phytochemistry and pharmacology of Chios mastic gum (Pistacia lentiscus var. Chia, Anacardiaceae): a review. Journal of Ethnopharmacology. 2020;254:112485 — comprehensive modern review.
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