Investigations will continue on naturally occurring food toxicants of importance to both animals and man. The toxins under consideration come from fungi that contaminate foods, from normal metabolites of food plants, and from plant stress metabolites that are induced by mechanical and chemical injury or by fungus infection of the plant. The principal toxins to be studied are lung and liver toxins that occur as stress metabolites of the sweet potato as well as chemical congeners occurring normally in other toxic plants. Emphasis will be placed on the biochemical mechanisms that activate the toxins and permit covalent binding to target tissues. Synthetic congeners will be prepared and tested for covalent binding and toxicity to ascertain structural features affecting toxicity. Collaborative arrangements continue with health authorities in Goroka, Papua, New Guinea to consider possible relationships among potentially toxic foods and certain endemic diseases among the Highland natives.