to investigate the efficacy of standard and low dosage of omeprazole in the healing of duodenal ulcer , 270 patients with endoscopically active duodenal ulcer were randomized to receive omeprazole , 10 mg or 20 mg every morning , or ranitidine , 150 mg twice daily , using the double-dummy technique .
C0013295
duodenal
C0034665
ranitidine