Acute and subacute toxicities to cats of T-2 toxin, 12-13 epoxytrichothec mycotoxin from fungi Fusarium species and others, were investigated. Major symptoms of toxicity in cats as the result of T-2 toxin were emesis, vomiting, diarrhea, anorexia, ataxia of the hind legs, discharge from the eyes and ejection of hemorrhagic fluid. Consecutive administration of the crude and pure sample of T-2 toxin in a sublethal dose caused a marked decrease in the number of circulating white blood cells. In the early stage of intoxication, a temporal leukocytosis was observed after each administration. Autopsy revealed extensive cellular damages in the bone marrow, intestine, spleen and lymph nodes. Greatly evident were meningeal hemorrhage of the brain, bleeding in the lungs and vacuolic degeneration of the renal tubles. Mycotoxicological significance of T-2 toxin and related trichothecenes is discussed in relation to the food-borne diseases in humans and farm animals.