A patient with chronic ulcerative colitis is described in whom microangiopathic hemolytic anemia developed in association with a severe acute exacerbation of the disease. The hemolysis and red cell fragmentation disappeared spontaneously, when the basic disease recovered. The pathologically altered vessels in the wall of the diseased colon are supposed to be responsible for the red cell fragmentation. This might be one, though apparently not very common, cause to the anemia present in patients with ulcerative colitis. Postoperatively, the histopathological features in the vessels of the diseased colon supported the concept of microangiopathic component in the development of the hemolytic anemia, although the changes this time were not strong enough to cause the clinical red cell fragmentation syndrome. © 1968 Informa UK Ltd.
