Food products are fundamentally mixtures of chemical compounds. That certain of these compounds may produce human toxicities has been known before recorded time. Because human diets are normally composed of large numbers of different foods, only minute quantities of any specific toxic materials are consumed. Thus, dilution exerts a significant protection effect against acute toxication. Toxicants are substances, which upon ingestion, produce changes in homeostasis that are threatening to the normal function of the organism. There are substantial differences in the toxicity thresholds of individuals to specific agents. Some of the naturally occurring food toxicants discussed are aflatoxin, caffeine, goitrin, oxalic acid, and solanine. Groups include toxic proteins, peptides, amides, amino acids, alkaloids, oligosaccharides, essential minerals and heavy trace elements, cyanogenic glycosides, phytoalexins, antinutrients, vitamins, mycotoxins, nitrates. There is little specific legislation that pertains to natural toxicants in food.