In a double-blind, double-dummy comparison of short-term ulcer healing, involving 50 patients treated with either De-Nol tablets (four times daily) or cimetidine tablets (400 mg, twice daily), no statistical difference in healing rates was observed after 8 weeks' treatment. There was, however, a numerical trend in favour of De-Nol (De-Nol, 100% healed; cimetidine, 88% healed). Statistical significance in favour of De-Nol was observed, however, in the reduction of antacid tablet consumption and relief of ulcer pain. No unwanted side effects were observed with either drug. This trial indicates that De-Nol and cimetidine are equally effective and useful in the short-term treatment of duodenal ulcer.