These processes are particularly well-studied as part of drug metabolism, as they influence the pharmacokinetics of a drug in the body. Certain approaches in alternative medicine claim to remove "toxins" from the body through herbal, electrical or electromagnetic treatments. These toxins are undefined and have no scientific basis, making the validity of such techniques questionable. There is little evidence for toxic accumulation in these cases, as the liver and kidneys automatically detoxify and excrete many toxic materials including metabolic wastes. Under this theory if toxins are too rapidly released without being safely eliminated (such as when metabolizing fat that stores toxins) they can damage the body and cause malaise. Therapies include contrast showers, detoxification foot pads, oil pulling, Gerson therapy, snake-stones, body cleansing, Scientology's Purification Rundown, water fasting, and metabolic therapy.