Herb library · Herb · Scutellaria lateriflora
Skullcap (American)
A North American mint-family plant sold for anxiety, stress and sleep, often mixed with valerian. Two small trials report some benefit for mood and sleep, and it has been linked to rare liver injury, often in products that turned out to contain other herbs.
Serious warning
NIH LiverTox rates skullcap a very likely but rare cause of liver injury, including at least one case of acute liver failure. Many cases involved products with several herbs, and some suspected skullcap products were found to contain germander or to be mislabeled.
Traditional use
Native to North America, where Native Americans used it for menstrual complaints, nervousness, and digestive and kidney problems. The name comes from the helmet-like shape of the flower's calyx. In 19th-century American medicine it was a nerve tonic; today it is sold for anxiety, stress and sleep, in teas, capsules and liquid extracts. Chinese skullcap (Scutellaria baicalensis) is a different species, also linked to liver injury.
What studies show
- Limited
Mood and anxiety: a 2014 crossover trial in 43 healthy, mostly calm adults found no significant difference from placebo on an anxiety scale, though overall mood scores improved while taking it. The authors call for studies in people who are actually anxious.
- Limited
Sleep: a 2025 trial in 66 adults with mild to moderate insomnia reported better sleep scores on a skullcap extract than on placebo over 8 weeks, with no side effects reported. It is a single study of one commercial product.
Be careful of
Cautions
- ConditionIn reported cases, liver injury began 1 to 12 weeks after starting it and usually cleared once it was stopped. See a doctor for yellowing skin or eyes, dark urine, or unusual tiredness while taking it.
- NoteProducts labeled skullcap have been found to contain germander or other species. There are more than 200 Scutellaria species with different chemistry and possible toxicity, so what is in the bottle matters.
- InteractionLiverTox notes its flavonoids are thought to act on the same brain receptors as benzodiazepine sedatives. Ask a pharmacist before combining it with sedatives or sleep medicines.
- Ask a clinicianTalk with a clinician or pharmacist before using this if you take prescription medicines, are pregnant or breastfeeding, or are giving it to a child.
From the old books
What herbals and dispensaries of the past printed. History, in their words.
“The official species is the Scutellaria lateriflora, but the larger part of the drug sold upon the market under that name is derived from two other species of Scutellaria.”
Sources
- Skullcap - LiverTox: Clinical and Research Information on Drug-Induced Liver Injury (opens in a new tab) · NIH · read September 25, 2026
- American Skullcap (Scutellaria lateriflora): a randomised, double-blind placebo-controlled crossover study of its effects on mood in healthy volunteers (Phytother Res, 2014) (opens in a new tab) · NIH · read September 25, 2026
- Efficacy and Tolerability of a Chemically Characterized Scutellaria lateriflora L. Extract-Based Food Supplement for Sleep Management (Nutrients, 2025) (opens in a new tab) · NIH · read September 25, 2026
Reviewed September 25, 2026.