During the academic year 1985-1986 at Gondar College of Medical Sciences Hospital gangrenous ergotism was clinically diagnosed in seven patients (5 males, 2 females) ranging in age from 20 to 45 years. Amputation and subsequent histological examination of the blood vessels revealed occluded tibial arteries by acute thrombosis without cellular reaction or inflammatory lesion of the arterial wall in 3 patients. Endangitis with organized arterial thrombosis and focal recanalization of the vessels was noted in the remaining four patients. The smaller arterial branches including the dorsal pedal artery appeared to be contracted with knobby projections into the lumen. The latter was occluded by chronic, organized thrombosis in all patients. The present finding indicates that thrombosis and its organization could be another pathogenic factor in the development of gangrene due to ergotism, which is a histological picture similar to that of thrombangitis obliterans.