There were 27 reports of adverse events related to herbal constituents; 18 adverse event reports associated with contamination, adulteration or substitution; and 12 case reports of adverse events related to herb-drug interactions.
Many herbal constituents have been associated with serious adverse effects. The clinical manifestations include cerebral arteritis, coma, confusion, encephalopathy, hallucinations, stroke, movement disorders, mood disturbances and seizures. The implied herbal remedies include: panax ginseng, eucalyptus, jimson weed, passionflower, neem tree oil, pennyroyal, liquorice, kava, ma-huang, ginkgo and St. John's wort.
Adverse effects may also be caused by contamination, adulteration or substitution of herbal medicines.
Numerous herb-drug interactions have been published as case reports in the medical literature.