A 12-week study with two weekly endoscopic assessments was performed in 138 patients to compare the efficacy of sucralfate fine granules (900 mg one-half hour before breakfast, lunch, and dinner, and at bedtime) versus placebo in the healing of gastric ulcers prestratified into corpus, prepyloric, and duodenal ulcer-associated. For corpus and prepyloric ulcers, the respective healing rates achieved by sucralfate at six weeks (69 and 80 percent) and at eight weeks (80 and 93 percent) were significantly (p less than 0.005) better than those obtained with placebo (33 and 25 percent at six weeks, and 41 and 33 percent at eight weeks). The design of the study permitted life-table analysis that further demonstrated the efficacy of sucralfate in these two ulcer types (p less than 0.0001). Symptomatic response was likewise significantly better with sucralfate than with placebo. Similar healing rates and symptomatic responses were observed for patients with duodenal ulcer-associated gastric ulcer but were not significantly better with sucralfate than with placebo. From 38 prospectively obtained clinical, personal, physiologic, and endoscopic characteristics, it was found that ulcer size and a history of pain had significant influence on healing with sucralfate. It is concluded that sucralfate is safe and effective for the treatment of corpus and prepyloric ulcers.