Objectives To evaluate the efficacy of teprenone on the healing of gastric ulcer and investigate its mechanisms in ulcer healing. Methods　One hundred and six patients with active gastric ulcer proven by endoscopy were recruited into this open, randomized, controlled, and multicentre clinical trial. Fifty-eight patients in Group A were given teprenone 50 mg thrice daily and cimetidine 800 mg at bedtime, and the other 48 patients cimetidine 800 mg at bedtime alone. All patients were examined by endoscopy to evaluate ulcer healing at the end of the 4th week and those whose ulcers had not yet healed were continuously treated till the end of the 8th week and were reexamined by endoscopy. Two pieces of tissue samples were taken from the gastric antral mucosa to measure the contents of hexosamine in gastric mucosa before and after the treatment. Tests of blood, urine and feaces as well as hepatic and renal functional tests were carried out before and after the treatment. Results　At the end of the 4th week, 72.4％ （42/58） of those on cimetidine＋teprenone and 52.1％ （25/48） on cimetidine alone had ulcers healed in comparison to 93.1％ （54/58） and 89.6％ （43/48） respectively after 8 weeks. The difference was significant at the end of the 4th week, indicating that the ulcer healed more rapidly in the combined treatment group. The stage S2 achievement rates were 34.5％ （20/58） and 10.4％ （5/48） after 4 weeks （P＜0.05） respectively, indicating that the quality of ulcer healing was much better in the combined group. The gastric mucosal hexosamine contents increased significantly after the treatment （17.79±2.00 μg/mg） as compared to that before the treatment （14.27± 2.47 μg/mg） in the combined treatment group, indicating that teprenone stimulates the synthesis of macromolecular glycoprotein in the healing process of gastric ulcer. Conclusion　It is reasonable to administer teprenone, an agent increasing mucosal resistance, concurrently with H2 blockers in the treatment of active gastric ulcer.