In the last decade an increased concern has been voiced against various environmental hazards, particularly chemicals that may cause harm to humans or animals. Numerous studies which have dealt with this subject invariably have focused on chemical contaminants of some component of a food chain. In contrast, much less attention has been paid to the potentially harmful substances that may occur in foodstuffs naturally. The purpose of this Handbook is to sensitize the reader to this problem and to provide a systematic overview of the most important naturally occurring food toxicants. The Handbook should be of interest to anybody who is concerned with nutritive and health aspects of food. Inasmuch as many of the discussed toxicants can be removed or destroyed by a suitable method of food rpocessing it should be of special value to food technologists.