Present FDA public policy maintains that L-Tryptophan is an untested, unapproved and hazardous drug. The analytical work done a few years ago by the Centers for Disease Control and the Mayo Clinic, research which traced the fall 1989 outbreak of the serious flu-like condition to contaminants found in batches of L-Tryptophan made by the Japanese company Showa Denko, has not convinced the FDA to allow L-Tryptophan back on the market. This decision is based primarily on the research of FDA and NIMH scientists who state that L-Tryptophan itself, irrespective of contaminants, is a dangerous substance. Other university-based research scientists disagree with these findings.