Skullcap

Skullcap can refer to 2 herbs: American skullcap (Scutellaria lateriflora) and Chinese skullcap (Scutellaria baicalensis). Both forms of skullcap are used to treat different conditions and are not interchangeable.

American skullcap is native to North America, but it is now widely cultivated in Europe and other areas of the world. It has been used for more than 200 years as a mild relaxant and as a therapy for anxiety, nervous tension, and convulsions. Studies show American skullcap has significant antioxidant effects, and may help protect against neurological disorders, such as Alzheimer's disease, Parkinson's disease, anxiety, and depression. There's even some evidence to suggest that American skullcap may inhibit food allergic response. Today, other herbs (such as valerian) are more commonly used, although American skullcap may be combined with other calming herbs in some preparations.

Most of the studies done on skullcap have examined Chinese skullcap. Native to China and parts of Russia, Chinese skullcap has been used in traditional Chinese medicine to treat allergies, infections, inflammation, cancer, and headaches. It may also have antifungal and antiviral effects. Animal studies suggest that Chinese skullcap may help reduce symptoms of diabetes and hypertension (high blood pressure), but scientists don't know if Chinese scullcap has the same effect in humans. In test tubes and animal studies, Chinese skullcap appears to have some cancer-fighting properties. More research is needed to determine any benefit.

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Plant Description

American skullcap derives its name from the caplike appearance of the outer whorl of its small blue or purple flowers. It is a slender, heavily-branched plant that grows to a height of 2 to 4 feet and blooms each July. It grows wild in woods and meadows.

Chinese skullcap is related to and resembles American skullcap, but it is a different plant. Its single stems bear a profusion of blue or purple flowers.

Parts Used

American skullcap

The leaves are used for medicinal purposes. These are harvested in June from a 3- to 4-year-old skullcap plant.

Chinese skullcap

The root is used medicinally.

Available Forms

American skullcap is available as a powder or liquid extract.

Chinese skullcap is available as a powder.

How to Take It

Pediatric

Neither American skullcap nor Chinese skullcap is recommended for children.

Adult

Skullcap is available as an encapsulated dried herb, tea, fluid extract, and tincture. Speak to your physician to find the right form and dose for your needs.

Chinese skullcap is often combined with other herbs into a preparation; follow dosing recommendations on the label.

Precautions

The use of herbs is a time-honored approach to strengthening the body and treating disease. However, herbs can trigger side effects, and can interact with other herbs, supplements, or medications. For these reasons, you should take herbs with care, under the supervision of a health care provider.

American skullcap

• In the past, American skullcap has been contaminated with germander (Teucrium), a group of plants known to cause liver problems. It is important that American skullcap be obtained from a reliable source.
• High doses of the tincture may cause giddiness, stupor, mental confusion, twitching, irregular heartbeat, and seizures.
• American skullcap should not be used during pregnancy and breastfeeding.

Chinese skullcap

• If you have diabetes, DO NOT take Chinese skullcap without your doctor's supervision. Chinese skullcap may lower blood sugar levels, raising the risk of hypoglycemia (low blood sugar).
• Avoid Chinese skullcap if you have stomach or spleen problems.
• Chinese skullcap should not be used during pregnancy or breastfeeding.

Possible Interactions

If you are being treated with any of the following medications, you should not use either American skullcap or Chinese skullcap without first talking to your health care provider.

Sedatives

Both American skullcap and Chinese skullcap can increase the effect of drugs that have a sedating effect, including:

• Anticonvulsants, such as phenytoin (Dilantin) and valproic acid (Depakote)
• Barbiturates
• Benzodiazepines, such as alprazolam (Xanax) and diazepam (Valium)
• Drugs to treat insomnia, such as zolpidem (Ambien), zaleplon (Sonata), eszopiclone (Lunesta), and ramelteon (Rozerem)
• Tricyclic antidepressants, such as amitriptyline (Elavil)
• Alcohol

The same is true of herbs with a sedating effect, such as valerian, kava, and catnip.

Drugs for Diabetes

Chinese skullcap can lower blood sugar, and could strengthen the effects of drugs taken for diabetes, increasing the risk of hypoglycemia (low blood sugar).

Supporting Research

Awad R, Arnason JT, Trudeau V, et al. Phytochemical and biological analysis of skullcap (Scutellaria lateriflora L.): a medicinal plant with anxiolytic properties. Phytomedicine. 2003;10:640-649.

Cauffield JS, Forbes HJ. Dietary supplements used in the treatment of depression, anxiety, and sleep disorders. Lippincotts Prim Care Pract. 1999;3:290-304.

Darzynkiewicz Z, Traganos F, Wu JM, Chen S. Chinese herbal mixture PC-SPES in treatment of prostate cancer (Review). Int J Oncol. 2000;17:729-736.

Enomoto R, Suzuki C, Koshiba C, et al. Wogonin prevents immunosuppressive action but not anti-inflammatory effect induced by glucocorticoid. Ann NY Acad Sci. 2007;1095:412-417.

Fisher C. Nettles - an aid to the treatment of allergic rhinitis. European Journal of Herbal Medicine. 1997;3:34-35.

Foster S, Tyler VE. Tyler's Honest Herbal. New York, NY: The Haworth Herbal Press; 1999:349-351.

Gao Z, Huang K, Xu H. Protective effects of flavonoids in the roots of Scutellaria baicalensis Georgi against hydrogen peroxide-induced oxidative stress in HS-SY5Y cells. Pharmacol Res. 2001;43:173-178.

Huang RL, Chen CC, Huang HL, et al. Anti-hepatitis B virus effects of wogonin isolated from Scutellaria baicalensis. Planta Med. 2000;66:694-698.

Ikemoto S, Sugimura K, Yoshida N, et al. Antitumor effects of Scutellariae radix and its components baicalein, baicalin, and wogonin on bladder cancer cell lines. Urology. 2000;55:951-955.

Kumagai T, Muller CI, Desmond JC, Imai Y, Heber D, Koeffler HP. Scutellaria baicalensis, a herbal medicine: anti-proliferative and apoptotic activity against acute lymphocytic leukemia, lymphoma and myeloma cell lines. Leuk Res. 2007;31:523-530.

Larrey D, Vial T, Pauwels A,et al. Hepatitis after germander (Teucrium chamaedrys) administration: another instance of herbal medicine toxicity. Ann Coll Physicians. 1992;117:129-132.

Lee E, Enomoto R, Suzuki C, et al. Wogonin, a plant flavone, potentiates etoposide-induced apoptosis in cancer cells. Ann N Y Acad Sci. 2007;1095:521-526.

Linnebur SA, Rapacchietta OC, Vejar M. Hepatotoxicity associated with Chinese skullcap contained in Move Free Advanced dietary supplement: two case reports and review of the literature. Pharmacotherapy. 2010;30:750, 258e-262e.

Lohani M, Ahuja M, Buabeid MA, et al. Anti-oxidative and DNA protecting effects of flavonoids-rich Scutellaria lateriflora. Nat Prod Commun. 2013;8:1415-1418.

Miller LG, Murray WJ, eds. Herbal Medicinals: A Clinician's Guide. New York, NY: Pharmaceutical Products Press; 1998.

Newall C, Anderson L, Phillipson J. Herbal Medicines: A Guide for Health-care Professionals. London: Pharmaceutical Press; 1996:239-240.

Peredary O, Persinger MA. 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. 2004;18:700-7055.

Rakel D. Integrative Medicine. 3rd ed. Philadelphia, PA: Elsevier Saunders; 2012.

Shao ZH, Vanden Hoek TL, Qin Y, et al. Baicalein attenuates oxidant stress in cardiomyocytes. Am J Physiol Heart Circ Physiol. 2002;282:H999-H1006.

Shin HS, Bae MJ, Jung SY, Shon DH. Inhibitory effect of skullcap (Scutellaria baicalensis) extract on ovalbumin permeation in vitro and in vivo. Food Chem. 2013;140:22-30.

Watanabe S, Kitade Y, Maski T, Nishioba M, Satoh K, Nishino H. Effects of lycopene and Sho-saiko-to on hepatocarcinogenesis in a rat model of sponstaneous liver cancer. Nutr Cancer. 2001;39:96-101

White L, Mavor S. Kids, Herbs, Health. Loveland, Colo: Interweave Press; 1998;22:40-41.

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

Zhang Z, Lian XY, Li S, Stringer JL. Characterization of chemical ingredients and anticonvulsant activity of American skullcap. Phytomedicine. 2009;16:485-493.

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Review Date: 1/1/2017  

Reviewed By: Steven D. Ehrlich, NMD, Solutions Acupuncture, a private practice specializing in complementary and alternative medicine, Phoenix, AZ. Review provided by VeriMed Healthcare Network. Also reviewed by the A.D.A.M. Editorial team.

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