Polyarteritis was described in 1866 by Kussmaul and Maier as periarteritis nodosa. Polyarteritis is a more exact name, since all coats of the vessel are involved and since nodules may not always be present. It is a widespread disease of arteries, and less commonly of veins, which may affect any organ or tissue of the body. This is a report of a case of polyarteritis with acute ulcerative enteritis. The diagnosis was not made until tissues secured at autopsy were examined. A review of the literature to November, 1950, confirmed our diagnosis. Polyarteritis is a rare causative agent in gastrointestinal ulceration. REPORT OF CASE History. S. L., a 52-year-old Negro housewife, was admitted to the hospital complaining of epigastric pain of two months' duration. She was awakened by severe epigastric pain which radiated along the margins of the costal cage. Except for varying intensity, it never completely disappeared. Episodes of