Crude or dehydrated bulbs of autumn crocus (Colchicum autumnale L.) were fed to eleven calves. All the calves developed severe diarrhea and died or euthanized within 63 hr. At necropsy, the gastro-intestinal mucosa was edematous and hemorrhagic. Histologically, necrosis and degeneration with karyopyknosis and karyorrhexis were shown in the basal cell layer of the tongue, esophagus, forestomach, renal pelvis, urinary bladder, neck cell layer of the abomasal gastric glands, and intestinal cryps. These findings were also seen in Kupffer cells, renal tubular epithelial cells, and lymphocytes in the lymphoid and hemopoietic systems. The lesion of the present acute crocus poisoning of cattle closely resembled those reported in humans with colchicine intoxication. Refined acetone extract of organs of poisoned cattle proved to contain colchicine and demecolcine by high performance liquid chromatography.