Few studies have been published on goldenseal's safety and effectiveness, and there is little scientific evidence to support using it for any health problem.
Clinical studies on a compound found in goldenseal, berberine, suggest that the compound may be beneficial for certain infections, such as those that cause some types of diarrhea, as well as some eye infections. However, goldenseal preparations contain only a small amount of berberine, so it is difficult to extend the evidence about the effectiveness of berberine to goldenseal.
The National Center for Complementary and Integrative Health (NCCIH) is funding research on goldenseal, including studies of antibacterial mechanisms and potential cholesterol-lowering effects. NCCIH is also funding development of research-grade goldenseal to facilitate clinical studies.
Goldenseal is considered safe for short-term use by adults at recommended dosages. Rare side effects may include nausea and vomiting.
There is little information about the safety of high dosages or the long-term use of goldenseal.
Goldenseal may cause changes in the way the body processes drugs, and could potentially alter the effects of many drugs.
Other herbs containing berberine, including Chinese goldthread (Coptis trifolia) and Oregon grape (Mahonia aquifolium), are sometimes substituted for goldenseal. These herbs may have different effects, side effects, and drug interactions than goldenseal.
Women who are pregnant or breast-feeding should avoid using goldenseal. Berberine, a chemical in goldenseal, can cause or worsen jaundice in newborns and could lead to a life-threatening problem called kernicterus.
Goldenseal should not be given to infants or young children.
Before taking any new medications, including natural health products, speak to your physician, pharmacist, or other health care provider. Tell your health care provider about any natural health products you may be taking.