OBJECTIVE: To evaluate the efficacy of Shengjiangxiexin decoction (SXD), prepared with a formula from Traditional Chinese Medicine (TCM), in reducing irinotecan-induced hematological and gastrointestinal toxicities in patients with UDP-glucuronosyltransferase (UGT)1A1*28 and UGT1A1*6 polymorphisms. METHODS: This clinical trial included 115 patients receiving irinotecan combined with 5-fluorouracil plus 1-leucovorin (FOLFIRI) treatment. All patients consented to UGT1A1*28 and *6 gene polymorphism detection prior to chemotherapy. SXD were administered from 1 day prior to chemotherapy to 6 day post chemotherapy. Chemotherapy induced adverse reactions (neutropenia, diarrhea, nausea, vomiting, anorexia and infection) were recorded, and short-term effect of chemotherapy was evaluated regularly." RESULTS: A total of 50 patients had *1/*1 wild genotype, 58 patients had single allele variants with genotype *1/*6 or *1/*28, and 7 patients had two alleles variants with genotype *6/*6, *28/*28 or *61* 28. In *1/*6 or *1/*28 patients (high risk group),.9 patients (15.5%) developed I II grade diarrhea and no patient developed severe diarrhea; neutropenia occurred in 19 patients (32.8%) and only 3 patients (8.6%) developed sever neutropenia. There were no significant differences in any toxic effects (neutropenia, diarrhea, nausea, vomiting, anorexia or infection) between *6 or *28 variant patients (high risk group) and wild type patients. No sever toxicity was found in high risk two alleles variants patients (*6/*6, *6/*28 or *28/*28). No significant differences were observed between UGT1A1*6/*28 polymorphisms and clinical response of chemotherapy. CONCLUSION: SXD could significantly reduce irinotecan-induced hematological and gastrointestinal toxicities in UGT1A1*28 or *6 variant patients (high risk group), while this treatment didn't affect clinical response of chemotherapy. (C) 2017 JTCM. All rights reserved.