Merriam-Webster's Collegiate Dictionary defines folk medicine as "traditional medicine as practiced nonprofessionally especially by people isolated from modern medical services and usually involving the use of plant-derived remedies on an empirical basis". As stated by David J. Hufford, professor in the Department of Humanities at the Penn State College of Medicine: Folk medicine is a form of complementary and alternative medicine that relies heavily (although not exclusively) on oral tradition. Strongly influenced by cultural norms and values, folk medicine generally comprises the "unofficial" or "lay" health beliefs and practices found in all societies. (Hufford DJ. "Folk medicine and health culture in contemporary society". Primary Care. 1997;24:723-741, cited in Report 13 of the Council on Scientific Affairs (A-97), American Medical Association)