Herbal medications may have a negative impact on patients going into surgery, scientists reported recently. The conclusions were drawn after researchers at the University of Chicago reviewed literature on the MEDLINE and Cochrane Collaboration databases published between January 1966 and December 2000. They used the search terms herbal medicine, phytotherapy, and alternative medicine and the names of the 16 most commonly used herbal medications. Additional data sources were obtained from manual searches of recent journal articles and textbooks. Studies, case reports, and reviews were selected that addressed the safety and pharmacology of 8 commonly used herbal medications for which safety information pertinent to the perioperative period was available. They found that the commonly used herbal medications ecchinacea, ephedra, garlic, ginkgo, ginseng, kava, St John's wort, and valerian might pose a health problem during the perioperative period. Direct effects reported include bleeding from garlic, ginkgo, and ginseng; cardiovascular instability from ephedra; and hypoglycemia from ginseng. St John's Wort was seen to increase the metabolism of drugs in the perioperative period. The researchers concluded that doctors should not only have explicit details of all herbal supplements taken by the patient prior to surgery but also a clear idea of the potential perioperative effects of these herbal medications on the human body.