(See also Overview of Dietary Supplements.)
Goldenseal, an endangered US plant, is related to the buttercup (Hydrastis canadensis). Its active components are hydrastine and berberine, which have antiseptic activity. Goldenseal is available in liquid, tablet, and capsule forms standardized to the active components.
Goldenseal can have many adverse effects, including nausea, anxiety, dyspepsia, uterine contractions, jaundice in neonates, and worsening of hypertension. If taken in large amounts, goldenseal can cause seizures and respiratory failure and may affect contraction of the heart. Women who are pregnant or breastfeeding, neonates, and people who have seizure disorders or problems with blood clotting should not take goldenseal. A recent in vitro study of the active ingredients of goldenseal, specifically berberine, indicates an increased risk of DNA damage leading to tumorigenic effects (4).
Goldenseal may interact with warfarin, and berberine may reduce the anticoagulant effect of heparin. In addition, a recent review of herbal extracts indicates that goldenseal, particularly berberine, is a weak inhibitor of CYP3A4 and CYP2D6 enzymes, which are important in the metabolism and elimination of many drugs (5).
Rehman J, Dillow JM, Carter SM, et al. Increased production of antigen-specific immunoglobulins G and M following in vivo treatment with the medicinal plants Echinacea angustifolia and Hydrastis canadensis. Immunol Lett 68(2-3):391-395, 1999.
Khin-Maung-U, Myo-Khin, Nyunt-Nyunt-Wai, et al. Clinical trial of berberine in acute watery diarrhoea. Br Med J (Clin Res Ed) 291(6509):1601-1605, 1995.
Rabbani GH, Butler T, Knight J, et al. Randomized controlled trial of berberine sulfate therapy for diarrhea due to enterotoxigenic Escherichia coli and Vibrio cholerae. J Infect Dis 155(5):979-984, 1987.
Chen S, Wan L, Couch L, et al. Mechanism study of goldenseal-associated DNA damage. Toxicol Lett 221(1):64-72, 2013.
Hermann R, von Richter O. Clinical evidence of herbal drugs as perpetrators of pharmacokinetic drug interactions. Planta Med 78(13) 1458-1477, 2012.