OBJECTIVE： To systematically evaluate the effectiveness of probiotics in adjunctive prevention and treatment of chemotherapy-induced diarrhea （CID）， and to provide evidence-based reference in the clinic. METHODS： All relevant randomized controlled trials （RCTs） of probiotics in adjunctive prevention and treatment of CID were collected by searching EMBase， Cochrane library， PubMed， CJFD， VIP， Wanfang databases and CBM. Meta-analysis were performed with Rev Man 5.2 software after data extraction and quality evaluation by Cochrane Hand book 5.0 “risk-bias assessment tool”. RESULTS： 10 RCTs were included， involving 871 patients. The results of Meta-analysis showed that addition of probiotics on the basis of conventional symptomatic therapy significantly reduced the total rate of diarrhea in cancer patients [OR＝0.31，95％CI（0.20，0.49），P＜0.001] and Ⅲ-Ⅳ diarrhea rate[OR＝0.09，95％CI（0.03，0.24），P＜0.001]， improved overall response rate [OR＝4.16，95％CI（2.40，7.23），P＜0.001] and complete remission rate [OR＝2.55，95％CI（1.66，3.90），P＜0.001]， with statistical significance. The probiotics had little effect onⅠ-Ⅱlevel diarrhea rate[OR＝0.86，95％CI（0.48，1.56），P＝0.62] and partial remission rate[OR＝1.00，95％CI（0.67，1.50），P＝1.00]， with statistical significance. CONCLUSIONS： The use of probiotics before chemotherapy can effectively prevent the occurrence of severe CID in cancer patients； in the treatment of CID， the combination of probiotics can also improve therapeutic efficacy of conventional symptomatic treatment.