OBJECTIVE Epidermal growth factor (EGF) and platelet-derived growth factor (PDGF) play important roles in the process of mucosal repair and restitution, and their biological effects are mediated by receptors located on the target cell surfaces. The purpose of this study was to assess the effect of the antiulcer agent, ebrotidine, on the expression of EGF and PDGF receptors with chronic ulcer healing. METHODS Chronic gastric ulcers were developed in the rat by acetic acid technique. The animal were divided into two groups and were treated twice daily for 14 consecutive days, either with ebrotidine at 100 mg/kg, or placebo. At different stages of treatment, the animals were sacrificed and used for the isolation and quantification of gastric mucosal EGF and PDGF receptors. RESULTS The binding assays revealed that ulcer healing was accompanied by an increase in mucosal expression of both types of receptors. A 1.7-1.8-fold increase in PDGF and EGF receptors occurred by the 4th day after the development of ulcer and reached a maximum of 3-fold increase by the 14th day, when the ulcer was essentially healed. Treatment with ebrotidine caused accelerated ulcer healing (7 days) which was accompanied by a significant enhancement in receptor expression. Compared to the controls, a 1.5-fold increase in EGF and 1.7-fold increase in PDGF receptor expression occurred by the 7th day of ebrotidine treatment, and a 1.4- to 1.5-fold increase was still observed at the 14th day of treatment. CONCLUSIONS The results suggest that ebrotidine is capable of enhancement of gastric mucosal proliferative activities associated with ulcer healing through the stimulation of EGF and PDGF receptor expression.