During an examination period of one year in a well defined population of 50 000 inhabitants 44 patients with colitis ulcerosa were diagnostically clarified and secured histologically. 37 patients (84.1%) could be treated and brought into a phase of remission with salazosulfapyridin (Azulfidine), glucocorticoids as well as a liberal gastroenterologic basic diet with restriction on dairy products and occasionally a diet, developed for astronauts. Only 7 patients (15.9%) had to be hospitalized for therapy because of accompanying illnesses, regression in the course of colitis and complications such as anemia and electrolyte imbalances. With view to the degree of severity, the majority of the patients showed signs of erosive and ulcerative changes as well as expanded pseudopolypic formations in the mucous membrane indicating the chronically continuing and chronically relapsing course of the disease. 54.5% of the affected showed endoscopical and histological changes in the rectosigmoid; an additional 27.2? had inflammatory changes up to the left colon flexure (see figure 2). Only 18.3% of the patients showed inflammatory attack of the entire colon. From the degree of severity of the inflammatory changes, the anatomic distribution and expansion in the large bowel, no difference in outpatient therapy with regard to its effectiveness can be seen.