A double-blind multiclinic trial compared the efficacies of pyridinolcarbamate and inositol niacinate in the patients with the ischemic ulcer due to chronic arterial occlusion. A thrice-daily dose of 1.5 g of pyridinolcarbamate or 1.2 g of inositol niacinate was given at random to the patients during cold seasons, and the effectiveness of treatment was assessed mainly on the basis of the clinical course of the ischemic ulcer and the rest pain. The patients were classified into 4- and 6-week groups. Beneficial results were recorded in 16 of 32 cases (50.0%) of the 4-week pyridinolcarbamate group, and in 24 of 42 cases (57.1%) of the 4-week inositol niacinate group. In the 6-week group favorable results were observed in 54 of 79 cases (68.4%) on pyridinolcarbamate, and in 36 of 74 cases (48.6%) on inositol niacinate. Although sympathectomy is currently indicated for these ischemic lesions, long-term treatment with pyridinolcarbamate is recommended on the basis of the finding that the 6-week treatment appears superior to the 4-week treatment and also to the 6-week treatment with inositiol niacinate.