Objective：To observe the effect of Aiyan bag navel therapy for the prevention of delayed-onset diarrhea caused by irinotecan.Methods：Divided 80 cases of patients with metastatic colorectal cancer into the control group and the treatment group randomly，with 40 cases in each group.The control group only received the chemotherapy according to the chemotherapy regimen including irinotecan(FOLFIRI)，without being given the prophylactic treatment； while the treatment group was additionally treated with self-made Aiyan bag navel therapy since the day before chemotherapy.Observed the incidence of delayed-onset diarrhea，compared the delay of chemotherapy plan and recorded the occurrence condition of side effects.Results：Compared with 47.50% and 12.50% of the incidence of delayed-onset diarrhea and severe diarrhea in the control group，25.00% and 2.50% of the incidence of delayed-onset diarrhea and severe diarrhea in the treatment group was decreased，difference being significant(P＜0.05).Compared with 7.50% and 25.00% of the incidence of interruption and delay in the control group，0 and 7.50% of the incidence of interruption and delay in the treatment group was decreased，difference being significant(P＜0.05).During the treatment process，the incidence of adverse reactions of nausea and vomiting in the treatment group was 10.00%，being lower than that of 27.50% in the control group，difference being significant(P＜0.05).There was no significant difference being found in the comparison of adverse reactions such as myelosuooression，oral ulcer and abnormal liver function in the two groups(P＞ 0.05).Conclusion：The application of Aiyan bag navel therapy for preventing delayed-onset diarrhea caused by irinotecan has satisfactory effect and it can improve the compliance of chemotherapy and reduce the incidence of nauseaand vomiting after chemotherapy.