Sixty five adult male rats were selected for the experiment. The rats were divided into three groups. Peptic ulcer was induced in the experimental group by means of injection of acetic acid to the submucosa of the stomach. Animals of the control group were injected with normal saline instead. Another control group consisted of normal rats without any treatment. All rats were killed at different time intervals (2-28 d) after the operation. The pancreas tissues were prepared for enzyme histochemical study. The results were observed as follows: Two to four days after the peptic ulcer operation, in the pancreatic A-cells, the activity of alkaline phosphatase (A1P) decreased and 5-nucleotidase (5-Nase) activity increased. A1P, adenosinc triphosphatase(ATPase),succinic and lactic dehydrogenases(SDH, LDH), glucose-6-phosphate and a-glycerophosphate dehydrogenases(G-6-PD,orGPD)acuvities were rasied in varying degrees and returned to normal level after 28 days of the operation. In the pancreatic B-cells, during the early stage of the peptic ulcer, acid phosphatase (AcP) and 5-Nase activities increased and ATPase activity declined. But after four days, AcP, 5-Nase, SDH and LDH activities declined, then began to recover and returned to normal level after twenty one days of the operation. In the normal saline operation control group, the changes of A- and B-cells, two to four days after the operation were the same as in the peptic ulcer group and returned to normal level during the period of six to ten days. The above histochemical changes showed that the pancreatic A- and B-cells played a certain role in the recovery of the experimental peptic ulcer.