During the early period of investigation of vitamins Funk demonstrated that nicotinic acid is a constituent of the vitamin B complex. At a later date Elvehjem and his collaborators1in their search for the antipellagra factor isolated nicotinic acid from highly active concentrates and found that a commercial preparation of this compound was highly effective in curing canine blacktongue. By analogy it was suggested that clinical trials should determine whether nicotinic acid would be equally effective against human pellagra.2More or less recently Spies and Smith and their colleagues, and others3as well, have demonstrated convincingly the highly effective role of nicotinic acid in the treatment of pellagra. In this section of the United States, where pellagra has often assumed the proportions of a major medical and psychiatric problem, the reports of their work and the results of local experiments produce the impression that a conspicuous advance