SUMMARY
The relationship between drug‐induced suppression of intragastric acidity and the rate of duodenal ulcer healing was examined using data for a single drug, ranitidine, from 156 clinical trials involving 16362 patients together with data on acid suppression from 37 studies of intragastric acidity in 630 subjects. In these studies ranitidine was given in doses ranging from 150 mg to 1200 mg per day administered in 9 different dosage regimens. The overall percentage of patients whose duodenal ulcers healed at 2 and 4 weeks on the different regimens was highly correlated with the percentage suppression of 24‐hour intragastric acidity induced by different regimens. Thus the therapeutic benefit of a given ranitidine dosage regimen in healing duodenal ulcers relates directly to its antisecretory effect.