Twenty-nine patients with attacks of distal ulcerative colitis were treated randomly with 3 g 5-aminosalicylic acid (5-ASA) or 30 mg of prednisolone phosphate sodium (PP) enemas (40 ml). Endoscopic, clinical, and histologic improvement were comparable in the two treatment groups. Our study showed that topical treatment with 5-ASA is as efficacious as PP in improving distal ulcerative colitis.