The effects of chlorbenzoxamine upon healing of peptic ulcer and upon ulcer-like complaints were studied by a double-blind trial which lasted 5 weeks. The material consisted of 112 patients with ulcer-type complaints, of whom 69 had definite roentgenological signs of gastric (13 patients) or duodenal ulcer (56 patients). Of the 69 ulcer patients 37 received the drug and 32 placebo. Ulcer showed roentgenological improvement in 73% of the drug group and in 66% of the placebo group, the difference being statistically insignificant. Four of the placebo group and one treated with the drug showed signs of penetration or perforation during the trial. Of the total group of 112 patients with ulcer-like complaints, 56 received the drug and 56 placebo. Improvement of complaints occurred in 98% of the treated and in 82% of the placebo group. The complaints remained unchanged in one of the treated and in ten of the placebo group, the difference being statistically significant (P<0.05).