Unlike the clinical trials of the previous decade, those conducted during the past 10 yr have had considerable impact on current therapeutic practices in the management of disorders of the upper gastrointestinal tract. This article reviews the clinical experience from 1975 to 1985 that pertains to the effectiveness of antacids compared to placebo and other anti-ulcer medications in the prevention and treatment of duodenal and gastric ulcers, stress ulceration and acute gastrointestinal bleeding, and gastroesophageal reflux disease.