The barium enema for the control of massive bleeding from diverticular disease of the colon was evaluated in 22 patients studied prospectively. Twenty-six of 28 acute bleeding episodes were arrested. The two patients who continued to bleed had an emergency colectomy while elective surgery was carried out in three patients after control of bleeding by the barium. The single complication was a laceration of the rectal mucosa by the enema tube. All patients survived. The probable mechanism is a tamponade of the bleeding by barium. Failure to control bleeding suggests that it will not subside spontaneously and in which case, early operative intervention should be undertaken with resection of all colon shown to contain diverticula.