Abstract: OBJECTIVE To observe the clinical efficacy and safety of the Hewei Yuyang formula combined with Omeprazole on the postoperative ulcers induced by gastric endoscopic submucosal dissection (ESD) for patients with spleen deficiency and heat constraint. METHODS Sixty post-operative ulcer patients with spleen deficiency and heat constraint type induced by gastric ESD were randomly divided into the control group and the treatment group with 30 cases in each group. The control group was given Omeprazole while the treatment group was given Omeprazole and Hewei Yuyang formula for four weeks. After treatment， the ulcer area reduction rates， the ulcer regenerated mucosal histological maturity， serum prostaglandin E₂ (PGE₂) levels， and traditional Chinese medicine (TCM) syndrome scores were compared. RESULTS After treatment， the ulcer area reduction rates in the two groups were decreased (P<0.05)， and the reduction rate in the treatment group decreased more significantly (P<0.05). The ulcer regenerated mucosal histological maturity in the treatment group was better than that of the control group (P<0.05). Serum PGE₂ levels in two groups were higher than those before treatment while the TCM syndrome scores were lower than those before treatment (P<0.05)， and the treatment group showed more significant differences (P<0.05). CONCLUSION Hewei Yuyang formula combined with Omeprazole has exact efficacy on the postoperative ulcer induced by gastric ESD for patients with spleen deficiency and heat constraint. The combined therapy can significantly speed up the healing of ulcers， improve the quality of healing， and relieve clinical symptoms with higher safety.