A few studies report interactions between berberine (a major component of goldenseal) and prescription or non-prescription medicines. One study reported that berberine may decrease the effectiveness of tetracycline antibiotics. Other laboratory studies report that berberine may alter liver metabolism, potentially affecting the levels of medications processed in the liver. Several studies actually report that goldenseal itself does not interact with medicines metabolized by the liver (including an antiviral drug used in HIV infection and digoxin). However, if you are taking prescription or non-prescription medications, do not use goldenseal unless you are under the supervision of a qualified health care provider.