Abstract: Objective 　To evaluate effect of glutamine on chemotherapy efficiency and toxicity in the course of treatment of gastrointestinal cancer. Methods 　A total of 60 cases with gast rointestinal cancer were randomized into two groups : chemotherapy and glutamine group ( G + C, 30 patient s) ; chemotherapy group (C, 30 patients) . Chemotherapy efficiency and toxicity were evaluated in two group s. Results 　The response rates were 46 % and 40 % in G+ C, and C group respectively, no signifcant difference was detected between two groups ( P > 0. 05) . However, the incidences of stomatitis were 50 % and 68 % in G+C, and C group respectively, and incidences of diarrhea were 40 % and 72 % respectively, significant difference was detected in stomatitis and diarrhea between two groups ( P < 0. 05) . Conclusion 　In the course of chemotherapy of gast rointestinal cancer, the incidences of stomatitis and diarrhea were reduced by administ ration of glutamine, and days in hospitals were decreased too. In short, Glutamine can be selected to use during chemotherapy in gast rointestinal cancer.