In eight fasting men with duodenal ulcer disease, oral administration of therapeutic dose of 49,5 mEq of neutralizing potency of either sodium bicarbonate or a preparation of calcium hidroxogluconaluminate did not produce significant increase in gastric acid secretion above basal levels for 90 minutes. This data support the conclusion that this specific antacid-containing calcium preparation does not stimulate the gastric secretion of acid.