In a study of forty-two patients with dyspepsia, hiatus hernia or duodenal ulcer, dicyclomine (Merbentyl) has been demonstrated to be effective in the control of the symptoms of this disorder. Under double-blind conditions an antacid or placebo supplement was provided and no significant difference in benefit was recorded. The antacid was given in a large tablet and this preparation was more conscientiously taken by patients, and this was equally true for large placebo tablets. Clearly patients like to take frequent treatment for dyspepsia, but symptom control is quite adequate if Merbentyl is given alone.