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. It is available in liquid, tablet, and capsule forms.
(See also Overview of Dietary Supplements.)
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 some relatively well-designed studies, berberine isolated from goldenseal reduced diarrhea, including diarrhea in people with irritable bowel syndrome.
Emerging evidence shows that in diabetic people, berberine can decrease fasting and postprandial glucose and hemoglobin A1c.
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 a seizure disorder or problems with blood clotting should not take goldenseal. The active component, berberine, may damage deoxyribonucleic acid (DNA), which can cause tumors to form.
Goldenseal may increase the effectiveness of drugs that prevent blood clots (such as warfarin), increasing bleeding. Goldenseal affects how the liver processes some drugs, which may result in other important drug interactions. The berberine in goldenseal may increase the hypoglycemic effects of antihyperglycemic drugs.
The following is an English-language resource that may be useful. Please note that THE MANUAL is not responsible for the content of this resource.
National Institutes of Health (NIH), National Center for Complementary and Integrative Health: General information on the use of goldenseal as a dietary supplement