In a series of experiments on rats,we have observed that the tensile strength and hydroxyproline content of left colonic anastomosis presented the lowest level on the 3rd and 4th postoperative days. Aprotinin,dimethyl sulfoxide,superoxide dismutase and vitamin A could improve the early coures of healing of colonic anastomosis;hydroxycortisone could retard the early course of healing of anastomosis and vitamin A antaonize the deleterious effect as mentioned above. Perioperative chemotherapy did not impair the early coures of healing of colonic anastomosis. The primary rasection and anastomosis of left colon for complete obstruction could be safety done if colonic content was decompressed before performing anastomosis and abdominal cavity was irrigated with antibiotic solutions afterwards. The mechanism of some factors influencing the healing of colonic anastomosis is discussed.