Skullcap

Scutellaria lateriflora / S. baicalensis

Family: Lamiaceae Part used: Aerial parts (American); root (Chinese)

Key Compounds

• Baicalin
• Baicalein
• Wogonin
• Wogonoside
• Scutellarein
• Scutellarin
• Apigenin
• Luteolin
• Oroxylin A
• Lateriflorin
• Scutellareside
• Catalpol

Traditional Use

• Classical kampo medicine — 黄芩 (ōgon, *Scutellaria baicalensis* root) is a Japanese Pharmacopoeia-approved crude drug and one of the most frequently used herbs in classical kampo formulas; appears in *Orengedoku-to*, *Saiko-ka-ryukotsu-boreito*, and many others; approved NHI coverage when prescribed as part of a kampo formula
• Anti-inflammatory — baicalin and baicalein demonstrate NF-κB inhibition and direct inhibition of cyclooxygenase (COX-1, COX-2) in laboratory studies; anti-inflammatory mechanism is among the most studied of any herbal flavonoid
• Neuroprotective — baicalein has shown neuroprotective activity in multiple laboratory models of ischemia and neurodegeneration; being researched for potential applications in stroke recovery and neurodegenerative conditions
• Anxiolytic (American skullcap) — *S. lateriflora* has clinical evidence for reducing anxiety without impairing cognition; used by Native American healers (Cherokee, Iroquois) for centuries; historically called 'mad dog skullcap' for supposed treatment of rabies symptoms
• Traditional Chinese medicine — 黄芩 (huangqin) used in TCM for over 2,000 years for fever, inflammation, and infection; classified as clearing heat and drying dampness; first described in *Shennong Bencao Jing* as a superior-class herb

Two plants share the name skullcap. Both are relevant. They are different.

Scutellaria lateriflora — American skullcap — is a North American wildflower. Cherokee and Iroquois healers used it for nervous conditions. 19th-century American Eclectic physicians called it the best nervine available. It was known as mad dog skullcap because it was used — probably ineffectively, but hopefully — for patients bitten by rabid animals.

Scutellaria baicalensis — Chinese skullcap, 黄芩 (ōgon in Japanese) — is a different plant, from northeast China and Siberia. Its root is a classical ingredient in Japanese kampo medicine. It contains baicalin and baicalein, two flavonoids with among the most extensively studied anti-inflammatory mechanisms in herbal pharmacology.

The common name connects them. The Lamiaceae family connects them. The medicinal use, the chemistry, and the traditional systems they belong to do not.

Meet the plants

Both are perennial herbs in the mint family, with small helmet-shaped flowers in blue-purple — the shape that gives the genus its name (scutella: a small dish or shield, for the cap-like calyx).

S. lateriflora: 30–60 cm, native to eastern North American woodlands. Aerial parts used. S. baicalensis: 20–40 cm, native to northeast Asia. Root used. The root is thick, fleshy, and yellow-brown when dried — the colour from the baicalin and baicalein pigments.

Mad dog skullcap

In 18th and 19th-century America, S. lateriflora was prescribed for a range of nervous conditions: anxiety, nervous exhaustion, epileptic symptoms, hysteria, and delirium tremens. Eclectic physicians — a 19th-century American medical tradition that integrated herbal and conventional medicine — considered it one of their most reliable nervine herbs.

The ‘mad dog’ name came from a belief, documented in herbals of the period, that it could treat hydrophobia (rabies). This was almost certainly false — rabies, once symptomatic, was fatal. What the plant may have done is provide antispasmodic and nervine relief from the convulsions and neurological symptoms — which would have been observed as some improvement, even if the outcome was unchanged.

The name stuck. The underlying nervine application was genuine and is now backed by clinical evidence: a 2014 randomised crossover trial by Brock et al. found that S. lateriflora significantly reduced anxiety without impairing cognition in healthy volunteers.

The Chinese kampo ingredient

黄芩 (ōgon) is among the most-used herbs in classical Japanese kampo formulas. It appears in formulas for inflammatory conditions, fever, and what classical medicine termed “heat” patterns: Orengedoku-to (黄連解毒湯), Saiko-ka-ryukotsu-boreito (柴胡加竜骨牡蠣湯), and others.

The classical description is “clearing heat and drying dampness.” The modern pharmacological explanation is NF-κB inhibition, COX inhibition, and antiviral activity. Both descriptions reflect real effects; they use different conceptual vocabularies.

Baicalin, present at 9–15% of dry root weight, is among the highest flavonoid concentrations in any medicinal plant. It is hydrolysed to baicalein by gut enzymes and microbiome activity after oral consumption. Baicalein directly inhibits COX-1 and COX-2 (the cyclooxygenase enzymes that produce prostaglandins — the targets of ibuprofen and aspirin). The mechanism is established at the molecular level.

The chemistry

Baicalin (baicalein-7-glucuronide) is the primary compound in Chinese skullcap root. High concentration, well-studied, with established anti-inflammatory mechanism.

Baicalein is the active aglycone, converted from baicalin in the gut. Directly inhibits COX-1 and COX-2; inhibits NF-κB; shows neuroprotective activity in laboratory models.

Wogonin and oroxylin A are related flavonoids contributing to the anti-inflammatory and antiproliferative activity.

Scutellarein and scutellarin are the primary flavonoids in American skullcap, less studied than baicalin but with documented antioxidant and nervine activity.

What people actually do with it

In kampo (ōgon): Prescribed as part of classical formulas at hospitals and clinics covered by Japan’s national health insurance. The most common route of access in Japan is through kampo prescription. Orengedoku-to (for inflammation, hypertension, skin redness) and Saiko-ka-ryukotsu-boreito (for anxiety, palpitations) are among the more commonly prescribed formulas containing it.

Chinese skullcap supplement: Standardised root extract capsules available at supplement retailers and TCM dispensaries. Typically 300–600 mg of extract per dose.

American skullcap supplement: Typically as tincture (most herb specialists consider fresh plant tincture superior; dried herb loses potency more quickly than many herbs) or dried herb capsules. 1–2 mL tincture, 2–3 times daily. Source verification important due to historical adulteration issues.

Note on sourcing: Products labelled ‘skullcap’ without species specification may be either species or a mixture. If using for anti-inflammatory applications aligned with kampo, ensure the product specifies S. baicalensis. If using for anxiety/nervine applications, ensure S. lateriflora.

Could you grow this yourself?

S. lateriflora grows in moist, partially shaded woodland conditions and can be cultivated in Japanese garden conditions with appropriate moisture. S. baicalensis grows in drier, sunny conditions similar to its native Siberian habitat and can be cultivated in well-drained soil in full sun. Both are attractive garden plants with blue-purple flowers in summer.

S. baicalensis root is harvested after 3–4 years. The root develops higher baicalin content with age.

Skullcap (黄芩/ōgon) in Japan

Japan’s primary relationship with skullcap is through 黄芩 (ōgon, S. baicalensis) in kampo.

The herb is Japanese Pharmacopoeia-approved as a crude drug and appears in dozens of classical kampo formulas prescribed through Japan’s national health insurance system. It is one of the standard ingredients of the classical kampo pharmacopoeia — not an obscure herb but a major daily-use component of one of the most frequently prescribed herbal systems in the world.

American skullcap is available as a Western herbal supplement in Japan but is not a classical Japanese medicinal herb and has no traditional Japanese name.

Things you’re probably wondering

What is the difference between American and Chinese skullcap? Different species, different medicinal parts, different primary uses. American (S. lateriflora): aerial parts, nervine/anxiolytic, Western herbal tradition. Chinese (S. baicalensis, ōgon): root, anti-inflammatory/antiviral, kampo and TCM.

What is baicalin? The primary flavone in Chinese skullcap root (9–15% dry weight). Converted to baicalein in the gut. Inhibits COX-1, COX-2, and NF-κB — well-established anti-inflammatory mechanisms.

What was the liver toxicity about? Adulteration with germander (Teucrium species), which does cause liver damage. Not a property of genuine skullcap. Quality sourcing matters.

What is the mad dog history? American skullcap was used in the 19th century as a supposed treatment for rabies. Ineffective against the disease; probably provided symptom relief from convulsions and agitation.

Botanical details

The full compound list

See Also

• Andrographis — NF-κB inhibitor with overlapping anti-inflammatory and antiviral applications
• Licorice Root — classical kampo co-ingredient; frequently combined with ōgon in formulas
• Valerian — nervine for anxiety and sleep; complements American skullcap’s applications

References

• Brock, C. et al. (2014). American skullcap (Scutellaria lateriflora): A randomised, double-blind placebo-controlled crossover study of its effects on mood in healthy volunteers. Phytotherapy Research, 28(5), 692–698.
• Zhao, Q. et al. (2016). Baicalin and baicalein: Biological activities and applications. Natural Product Reports, 33(5), 580–594.
• Bensky, D. et al. (2004). Chinese Herbal Medicine: Materia Medica (3rd ed.). Eastland Press.
• Li, B.Q. et al. (2000). Flavonoid baicalin inhibits HIV-1 infection at the level of viral entry. Biochemical and Biophysical Research Communications, 276(2), 534–538.