Some effects of hypoglycin on skin slices maintained in vitro were measured. Hypoglycin inhibited the endogenous respiration of skin slices but had no effect on skin respiration in the presence of added glucose. Ammonia was liberated when hypoglycin was incubated with skin slices. Hypoglycin inhibited the production of [14C] CO from [U-14C] palmitate by skin slices. The significance of these results in relation to theories of the toxicology of hypoglycin is discussed.