Skullcap: History and Traditional Use

"Skullcap" is two histories wearing one name. American skullcap, Scutellaria lateriflora, is a streamside mint of North America whose record begins with Cherokee and Iroquois medicine, passes through a strange episode as a supposed cure for rabies, and settles in the nineteenth century into its lasting role as a nervine — a herb for frayed nerves. Chinese skullcap, Scutellaria baicalensis or huang qin, is a different plant, used as a yellow root rather than a leafy top, with a record some eighteen centuries long in the classical texts of Chinese medicine. This article follows both threads, and where a claim rests on tradition rather than evidence, it says so.

Table of Contents

  1. Two Skullcaps, One Name: Botany and Etymology
  2. Cherokee and Iroquois Medicine
  3. The Mad-Dog Years: Van Derveer and Rabies (1772–1920s)
  4. The Nervine Century: Eclectics and Physiomedicalists
  5. Official Status: Pharmacopeia and National Formulary (1863–1947)
  6. Huang Qin: The Far Older Chinese Record
  7. Into the Laboratory: Scutellarin, Baicalin and Baicalein (1889–1923)
  8. The Germander Problem: How a Safe Herb Got a Dangerous Reputation
  9. Tradition Meets the Trial
  10. Skullcap Today
  11. Key Research Papers
  12. Connections
  13. Featured Videos

Two Skullcaps, One Name: Botany and Etymology

The genus Scutellaria belongs to the mint family, Lamiaceae, and is large — estimates run from roughly 300 to more than 400 species across the temperate world. Its name comes from the Latin scutella, "a little dish." The calyx (the green cup that holds the flower) carries a raised crest on its upper lip, so that it looks like a tiny lidded dish or, to English eyes, a miniature helmet. That helmet gave the plants their common name and its older forms, scullcap, helmet flower and hoodwort.

Carl Linnaeus named Scutellaria lateriflora in Species Plantarum in 1753; the epithet means "side-flowering," for the one-sided rows of small blue flowers along its branches. It is a slender perennial of wet ground across much of Canada and the United States. In 1775 the German naturalist Johann Gottlieb Georgi, in the account of his travels through the Russian Empire, named Scutellaria baicalensis after Lake Baikal, near which he collected it. That species is native to the Russian Far East, Mongolia, northern China and Korea, and is used quite differently: the American herb is taken as the dried leafy tops, the Chinese herb as a thick, bright-yellow root.

Whenever this article says skullcap without qualification, it means the American plant; the Chinese plant is always Chinese skullcap or huang qin.

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Cherokee and Iroquois Medicine

Before any European physician wrote about it, S. lateriflora was a medicine of the peoples who lived where it grew. The records were set down by twentieth-century ethnobotanists and gathered in Daniel Moerman's Native American Ethnobotany database.

Among the Cherokee, Paul Hamel and Mary Chiltoskey's Cherokee Plants and Their Uses (1975) records an infusion of the root taken for the monthly period and for diarrhoea, a decoction taken "for nerves," a compound for breast pain, a root compound used as a kidney medicine, and a preparation to help expel the afterbirth. Linda Averill Taylor's 1940 survey of southeastern tribes likewise lists a root decoction taken as an emetic to expel the afterbirth. Among the Iroquois, James Herrick's Iroquois Medical Botany (1977) records an infusion of the powdered roots taken to prevent smallpox — a disease that arrived with Europeans, which dates that use to the colonial period or later — and another taken "to keep the throat clean."

Note that Indigenous practice used the root as often as the herb, and that the calming use ("for nerves") sits beside gynaecological and digestive uses Western herbalism later dropped. These are records of practice, not evidence of effect.

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The Mad-Dog Years: Van Derveer and Rabies (1772–1920s)

Skullcap's entry into written medicine is one of the odder episodes in American herbal history, and it explains a name the plant still carries: mad-dog skullcap, or simply mad weed. Rabies — then called hydrophobia, for the terror of water in its final stage — was an incurable horror caught from the bite of a "mad dog."

The fullest early account is in Constantine Rafinesque's Medical Flora (1828–1830). Rafinesque wrote that the plant had "lately become famous as a cure and prophylactic against hydrophobia," a property "discovered by Dr. Vandesveer, towards 1772," who was said to have used it until his death in 1815 and to have prevented 400 people and 1,000 cattle from developing the disease after being bitten; his son was credited with 40 more cases in New York and New Jersey. (The New Jersey physician's name is spelled Vandesveer, Van Derveer and Vanderveer in the old sources.) Rafinesque also recorded the sceptics, Dr. William Barton and Dr. Tully, who had "strenuously" denied the claim. William Cook's Physiomedical Dispensatory (1869) repeats the outline — "first commended by Dr. Vandesveer in 1772" and defended by Dr. White of Fishkill and Rafinesque — but adds that "the good opinion of it once entertained has not been fully confirmed."

The rest of the century quietly buried the claim. King's American Dispensatory (1898) called it "still a matter of uncertainty," and Harvey Wickes Felter's Eclectic Materia Medica (1922) summed up "a great reputation as a cure for hydrophobia, based upon the reports of New Jersey physicians, a claim which time has totally failed to sustain."

The episode shows how a reputation is built on uncontrolled observation — most animal bites do not transmit rabies, so any remedy given afterwards will appear to "work" — and it is a reminder that skullcap is not a treatment for rabies; the only effective response to an exposure is prompt post-exposure vaccination.

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The Nervine Century: Eclectics and Physiomedicalists

When the rabies claim fell away, what remained was the use that has defined skullcap ever since. Nineteenth-century America's two botanical schools — the Eclectics, who built a materia medica largely from native plants, and the Physiomedicalists, heirs of Samuel Thomson — both classed skullcap as a nervine — a period term for a remedy that steadies the nervous system without stupefying it, as distinct from a narcotic.

Cook (1869) recommended it for "restless and wakeful conditions, with feebleness; and for all forms of nervousness with fatigue or depression," and, combined with lobelia or blue cohosh, for hysteria, chorea and convulsions. King's American Dispensatory (1898) called it "tonic, nervine, and antispasmodic," useful "in chorea, convulsions, tremors, intermittent fever, neuralgia, and many nervous affections," and noted that in delirium tremens "an infusion drank freely will soon produce a calm sleep." Felter (1922) gave the indication herbalists still quote: "Nervousness attending or following illness, or from mental or physical exhaustion ... tremors; hysteria."

The preparations were an infusion, a tincture, a fluid extract and, peculiar to the Eclectics, "Scutellarin," a crude concentrated extract sold in grain doses — not the pure flavonoid of the same name isolated later. Even then identity was a problem: King's noted in 1898 that "the larger part of the drug sold upon the market under that name" came from other Scutellaria species. All of this is tradition, built on clinical impression rather than trials, but it was consistent for a century and it set the question researchers would eventually ask.

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Official Status: Pharmacopeia and National Formulary (1863–1947)

For the better part of a century skullcap was an official drug in the United States. The Pharmacopoeia of the United States adopted by the national convention of 1860 — the fourth decennial revision, entered for copyright in 1863 and printed in 1864 — lists "Scutellaria. Scullcap. The herb of Scutellaria lateriflora." It remained through the eighth revision of 1905, was dropped from U.S.P. IX in 1916 and in the same year, as the 1918 Dispensatory records, was "introduced into the N.F. IV" — the National Formulary, the secondary compendium for preparations still in use but no longer first-rank — where it stayed through N.F. VII. The eighth edition, published in 1946 and official from 1 April 1947, lists Scutellaria among the "articles not admitted" — the end of an official career of roughly 84 years.

The trajectory is a barometer of professional opinion: admitted at the height of botanical medicine, demoted when pharmacology demanded isolated principles and measurable effects, dropped when neither had been shown. That does not prove the herb useless — only that by the 1940s no one had done the work to prove it useful.

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Huang Qin: The Far Older Chinese Record

While the American herb has a written history of two and a half centuries, the Chinese skullcap's reaches back about eighteen. Huang qin (黃芩, "yellow" plus an old character for a medicinal herb) is recorded in the Shennong Bencao Jing, the Divine Farmer's Classic of Materia Medica. That text is traditionally attributed to the legendary emperor Shennong, but scholars regard it as a compilation of older oral tradition written down in the Han period; most date it to the first or second century CE, and the reviews of huang qin cited below place it around 200 CE. The original is lost and survives only in later reconstructions. Its huang qin entry, as summarised by modern reviewers, treated the root as bitter and cold and gave it for lung and liver complaints.

In the language of traditional Chinese medicine — that system's own framework, not a modern mechanism — huang qin "clears heat and dries dampness," meaning feverish, inflamed, diarrhoeal and bleeding conditions, and it appears in some of the oldest formulas still in use. Zhang Zhongjing's Shanghan Lun (Treatise on Cold Damage, around 200 CE) contains Xiao Chai Hu Tang (Minor Bupleurum Decoction, sho-saiko-to in Japan), and Huang Qin Tang (Scutellaria Decoction) is a four-herb formula of the same age — the "1,800-year-old" recipe that Yale researchers later standardised as PHY906. Li Shizhen's Bencao Gangmu (Compendium of Materia Medica, 1593) records huang qin for diarrhoea, dysentery, haemorrhage, insomnia, inflammation and respiratory infections, and preserves the story that Li himself, at twenty, was cured of a lung infection by it.

This is a long, literate tradition of use, not clinical evidence — and it has nothing to do with the calming use of the American herb, which the Chinese texts never knew.

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Into the Laboratory: Scutellarin, Baicalin and Baicalein (1889–1923)

The chemical story begins modestly, with a crystalline bitter glucoside that C. O. Myers and H. R. Gillespie reported from the American herb in the American Journal of Pharmacy in 1889. The first real landmark came from Vienna. In 1901 the botanist Hans Molisch and the chemist Guido Goldschmiedt published "Über das Scutellarin" in Monatshefte für Chemie, naming scutellarin, a substance found throughout the skullcaps and other mints; Goldschmiedt returned to its structure with Ernst Zerner in 1910. Scutellarin is a flavone glucuronide — a flavonoid pigment attached to a sugar acid — and the pure namesake of the crude Eclectic product above.

The Chinese root yielded its chemistry a little later. According to the 2018 review by Wang and colleagues, baicalin was first reported from S. baicalensis by the Italian chemist G. Bargellini in 1919, and its structure was established in 1923 by the Japanese chemists K. Shibata, S. Iwata and M. Nakamura, who described it in Acta Phytochimica as "a new flavone-glucuronic acid compound from the roots of Scutellaria baicalensis." Baicalin is the glucuronide of baicalein; the pair, with wogonin and its glucuronide wogonoside, are the yellow flavones that colour the root and account for most of the pharmacology studied since. Both also occur, in smaller amounts, in the American herb.

For the American herb the pharmacological interest turned, in the early 2000s, to the nervous system. Awad and colleagues (2003) reported anxiety-reducing effects of S. lateriflora extracts in rats and quantified baicalin and the amino acid GABA in them, noting that baicalin and baicalein bind the benzodiazepine site of the GABA-A receptor; Gafner and colleagues the same year showed skullcap flavonoids binding a serotonin receptor. Plausible mechanisms, not proof of effect in people — but for the first time the old nervine had a chemical rationale.

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The Germander Problem: How a Safe Herb Got a Dangerous Reputation

For most of the twentieth century skullcap was an obscure, gentle herb sold in sedative blends. Then, in 1989, physicians at the Royal Infirmary of Edinburgh reported in the BMJ patients who developed hepatitis while taking herbal sedative tablets whose listed ingredients included skullcap. A similar Dutch report followed in the BMJ in 1996, and in 1999 the American Journal of Medicine carried a case of fatal liver failure in a woman taking a multi-herb product that listed skullcap. Skullcap acquired a reputation as a liver toxin.

The other half of the story was unfolding in France, where germander (Teucrium chamaedrys), an unrelated mint-family plant, was widely taken as a weight-loss remedy. In 1992 Larrey and colleagues reported seven cases of hepatitis after germander in the Annals of Internal Medicine, three of them relapsing on re-exposure. Germander's toxicity is genuine: its neoclerodane diterpenes (teucrin A among them) are turned by liver enzymes into reactive metabolites that injure liver cells.

The two stories met when investigators asked what was actually in the "skullcap" products. Dried, cut skullcap and germander — especially the North American Teucrium canadense — look alike, and germander was cheaper. In 2009 U.S. Department of Agriculture chemists working with the American Herbal Pharmacopoeia's Roy Upton confirmed that skullcap "has occasionally been adulterated" with germander and published a chromatographic fingerprint that detects as little as 5 per cent of it; Brock and colleagues added an authentication method for commercial products in 2013. Genuine S. lateriflora contains no clerodane diterpenes, and no mechanism by which it would injure the liver has been established. The prevailing view, set out in the National Library of Medicine's LiverTox database, is that the reports are most plausibly explained by germander substitution or other ingredients in the same products — with the caveat that the original tablets were not always analysed.

The lesson outlived the affair: it is why the American Herbal Pharmacopoeia devoted a monograph to skullcap's identity in 2012, and why verifying what is in a supplement comes first. Chinese skullcap has a separate file: a few case reports since 2010 describe liver injury in people taking multi-ingredient joint supplements containing S. baicalensis extract — a different plant and a different question.

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Tradition Meets the Trial

For a herb used for 250 years, American skullcap has been tested in people astonishingly little. The first controlled study came in 2003: Wolfson and Hoffmann published in Alternative Therapies in Health and Medicine a double-blind, placebo-controlled study in healthy volunteers, and reported "noteworthy anxiolytic effects." It was small and in healthy people, but it was the first blinded test of the Eclectics' question.

The better-known trial is Brock, Whitehouse, Tewfik and Towell's crossover study at the University of Westminster, published in Phytotherapy Research in 2014. Forty-three healthy volunteers took 350 mg of S. lateriflora or placebo three times a day for two weeks each. On the Beck Anxiety Inventory there was no significant difference from placebo — unsurprisingly, since 81 per cent of participants were at most mildly anxious. On the Profile of Mood States, total mood disturbance fell significantly with skullcap but not placebo, with no loss of energy or cognition. The authors called for a trial in genuinely anxious people; it has not been done. The honest position today: a long traditional record, a plausible mechanism, two small positive-leaning studies, and no adequately powered trial in patients with an anxiety disorder.

Chinese skullcap has gone a different way. Its flavones have a large laboratory literature on anti-inflammatory, antioxidant, antiviral, antibacterial, anticonvulsant, neuroprotective and anticancer activity in cells and animals, summarised by Zhao, Chen and Martin (2016) and Wang and colleagues (2018). Human evidence is far thinner, but one line is notable: PHY906, a standardised preparation of the four-herb Huang Qin Tang with huang qin as its key component, was reported in Science Translational Medicine in 2010 to reduce the gut toxicity of the chemotherapy drug irinotecan in a phase I/II study and in mice — a Han-dynasty diarrhoea formula answering a twenty-first-century problem. This site's Baicalin and Chinese Skullcap Research page covers that literature in detail.

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Skullcap Today

American skullcap is once again what the Eclectics made it: a mild nervine, taken as a tea, tincture or capsule for everyday nervous tension and restless sleep, and often blended with valerian, passionflower or lemon balm. It has no official pharmacopoeial standing in the United States today; its standards of identity come from the American Herbal Pharmacopoeia, not a regulator. Chinese skullcap remains one of the most-prescribed roots in East Asian medicine, in such demand that wild stands have been over-collected and the plant is now widely cultivated.

The history leaves three legacies. The rabies episode is a caution against reading reputation as proof. The pharmacopoeial rise and fall shows a herb dropped for lack of evidence rather than evidence of harm. And the germander affair matters most: the danger in "skullcap" has never been shown to lie in Scutellaria lateriflora itself, but in what has been sold under its name. Know the Latin name, the part and the supplier — the rules that would have served a buyer in 1898.

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Key Research Papers

The modern scholarship behind the article; the historical primary texts are named in the article and linked under External Resources where a free scan exists.

  1. Upton R, DAyu RH (2012). Skullcap Scutellaria lateriflora L.: An American nervine. Journal of Herbal Medicine. — doi:10.1016/j.hermed.2012.06.004
  2. Molisch H, Goldschmiedt G (1901). Über das Scutellarin, einen neuen Körper bei Scutellaria und anderen Labiaten. Monatshefte für Chemie. — doi:10.1007/bf01519774
  3. Wang ZL, Wang S, Kuang Y, Hu ZM, Qiao X, Ye M (2018). A comprehensive review on phytochemistry, pharmacology, and flavonoid biosynthesis of Scutellaria baicalensis. Pharmaceutical Biology. — doi:10.1080/13880209.2018.1492620
  4. Awad R, Arnason JT, Trudeau V, Bergeron C, Budzinski JW, Foster BC, Merali Z (2003). Phytochemical and biological analysis of Skullcap (Scutellaria lateriflora L.): A medicinal plant with anxiolytic properties. Phytomedicine. — doi:10.1078/0944-7113-00374
  5. Wolfson P, Hoffmann DL (2003). An investigation into the efficacy of Scutellaria lateriflora in healthy volunteers. Alternative Therapies in Health and Medicine. — PubMed PMID: 12652886
  6. Brock C, Whitehouse J, Tewfik I, Towell T (2014). American Skullcap (Scutellaria lateriflora): A randomised, double-blind placebo-controlled crossover study of its effects on mood in healthy volunteers. Phytotherapy Research. — doi:10.1002/ptr.5044
  7. MacGregor FB, Abernethy VE, Dahabra S, Cobden I, Hayes PC (1989). Hepatotoxicity of herbal remedies. BMJ. — doi:10.1136/bmj.299.6708.1156
  8. Larrey D, Vial T, Pauwels A, Castot A, et al. (1992). Hepatitis after germander (Teucrium chamaedrys) administration: another instance of herbal medicine hepatotoxicity. Annals of Internal Medicine. — doi:10.7326/0003-4819-117-2-129
  9. Lin LZ, Harnly JM, Upton R (2009). Comparison of the phenolic component profiles of skullcap (Scutellaria lateriflora) and germander (Teucrium canadense and T. chamaedrys), a potentially hepatotoxic adulterant. Phytochemical Analysis. — doi:10.1002/pca.1127
  10. Zhao Q, Chen XY, Martin C (2016). Scutellaria baicalensis, the golden herb from the garden of Chinese medicinal plants. Science Bulletin. — doi:10.1007/s11434-016-1136-5

PubMed Topic Searches

  1. PubMed: Scutellaria lateriflora ethnobotany and traditional use
  2. PubMed: Skullcap, germander adulteration and hepatotoxicity
  3. PubMed: Scutellaria baicalensis history of pharmacology

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