Scutellaria is a rather diverse genus, including about 360 species of herbs and shrubs widely distributed on several continents. Scutellaria lateriflora belongs to one of several species groups native to eastern North America. It is a woodland herb with small, attractive bilabiate flowers; unlike most related species, the flowers are borne in one-sided lateral racemes. The name, imagined by some to indicate toxicity, actually refers to a rounded projection on the upper lip of the calyx, which was fancied to be skull-shaped. After flowering, the asymmetrical calyx expands to cover the nutlets. Skullcap has traditionally been used as a nerve tonic or sedative, for seizures and epilepsy, and for a variety of nervous conditions. It was once widely regarded as a treatment for rabies, but what effect it had is not clear; it seems most likely that in an era without modern pharmaceutical sedatives, an herb with calming and seizure-preventing effects simply made the patient?s inevitable death less agonizing.

None of skullcap?s folk uses has so far been scientifically verified. Limited animal research shows an anti-anxiety effect, as does one very limited human study; one study involving rats with induced epilepsy showed that skullcap suppressed seizures during the period of use. There have been a number of case reports of liver disease associated with skullcap products, and skullcap is sometimes claimed to be hepatotoxic. However, there is no evidence of this. Rather, material in commerce has often been contaminated with American germander (Teucrium canadense L., sometimes called pink skullcap), a similar-looking species which does contain hepatotoxic compounds. Since skullcap is commonly wild-collected rather than cultivated, accidental inclusion of germander in commercial products remains a serious potential risk if manufacturers do not take positive steps to avoid it.

Selected References

Awad, R., J. T. Arnason, V. Trudeau, C. Bergeron, J. W. Budzinski, B. C. Foster, and Z. Merali. 2003. Phytochemical and biological analysis of skullcap (Scutellaria lateriflora L.): a medicinal plant with anxiolytic properties. Phytomedicine 10:640-649.

Epling, C. 1942. The American species of Scutellaria. Univ. Calif. Publ. Bot. 20:1-146.

Gafner, S., C. Bergeron, L. L. Batcha, C. K. Angerhofer, S. Sudberg, E. M. Sudberg, H. Guinaudeau, and R. Gauthier. 2003. Analysis of Scutellaria lateriflora and its adulterants Teucrium canadense and Teucrium chamaedrys by LC-UV/MS, TLC, and digital photomicroscopy. J. AOAC Int. 86:453-460.

Paton, A. 1990. A global taxonomic investigation of Scutellaria (Labiatae). Kew Bull. 45:399-450.

Peredery, O., and M. A. Persinger. 2004. Herbal treatment following post-seizure induction in rat by lithium pilocarpine: Scutellaria lateriflora (Skullcap), Gelsemium sempervirens (Gelsemium) and Datura stramonium (Jimson Weed) may prevent development of spontaneous seizures. Phytother. Res. 18:700-705.

Wolfson, P., and D. L. Hoffmann. 2003. An investigation into the efficacy of Scutellaria lateriflora in healthy volunteers. Altern. Ther. Health Med. 9:74-78.