(See also Overview of Medicinal Herbs and Nutraceuticals.)
Goldenseal, an endangered plant, is related to the buttercup. Its active components are hydrastine and berberine, which have antiseptic activity. Berberine is also active against diarrhea.
Goldenseal is used as an antiseptic wash for mouth sores, inflamed and sore eyes, wounds, and irritated skin and as a douche for vaginal infections. It has been combined with echinacea as a cold remedy, but the effectiveness of goldenseal as a cold remedy has not been proved. Goldenseal is also used as a remedy for indigestion and diarrhea. In two relatively well-designed studies, berberine isolated from goldenseal reduced diarrhea.
Goldenseal can cause many side effects, including digestive irritation and upset, contractions of the uterus, jaundice in newborns, and worsening of high blood pressure (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, newborns, and people who have heart disease, a seizure disorder, or problems with blood clotting should not take goldenseal.