Objective To investigate the effect of imbedding chemotherapy of sustained release of 5-fluorouracil on the healing of colonic stoma in dog. Methods Twenty-eight adult hybrid dogs were randomly divided into chemotherapy group （n=22) and control group (n=6). The canine sigmoid colon were firstly detached and then anastomosed via median abdominal incision, 200 mg sustained release of 5-fluorouracil was imbedded in the mesentery 1.0-1.5 cm away from colonic stoma in chemotherapy group, whereas the control substance was injected into the dogs in control group. Tissue samples were collected from mesentery and stomas on 3, 5, 7, 10 and 15 days after operation, respectively, in order to observe the healing of stoma. The drug concentrations in the stoma and in the tissues that were 0, 1, 3, 5, 7, 10 and 15 cm away from the imbedding point were also measured by high performance liquid chromatographymethod at different phases. Results The tissues from colonic stoma only showed inflammatory reaction at early stage, with no necrosis and cellular degeneration. It was observed that the stoma healed basically on the tenth day after operation. The drug concentrations in the tissues gradually decreased at the range of 0-15 cm over time, but all of which were higher than the anti-tumor effective concentration （0.10 μg/g）. Conclusion The imbedding chemotherapy of sustained release of 5-fluorouracil in mesentery has little effect on the healing of stoma, and it could remain an effective anti-tumor concentration in a period of time.