The Efficacy and Safety of a Compound Glutamine Capsule in the Primary Prevention of Chemotherapy-induced Mucositis

Inclusion Criteria: * Age: 18-75 years old; Sex: Male or female * Pathologically confirmed gastric adenocarcinoma or colorectal adenocarcinoma. * Patients are ready to receive chemotherapy regimens containing platinum or irinotecan (targeted therapy could be used at the same time). Patients have not received any anti-cancer treatment before. * patients are planned to receive the same chemotherapy regimen at least 2 cycles * A baseline Eastern Cooperative Oncology Group (ECOG) performance status of 0-2. * Adequate haematopoietic function of bone marrow: neutrophils≥1.5x109 / L, platelets≥75x109 / L; normal liver and kidney function: TBIL≤ 1 upper limit of normal (ULN); ALT and AST ≤2.5 ULN; creatinine≤1.5 ULN. Exclusion Criteria: * (Patient-Generated Subjective Global Assessment, PG-SGA)\>9 or severe malnutrition (weight loss \> 10% or serum albumin \< 30 g/L or body mass index \< 18.5 kg/m2); * Patients with severe heart, lung and brain diseases; chronic hepatitis infection, liver cirrhosis, chronic nephritis, kidney dysfunction, etc; * Patients with infection-related fever; * Patients who are known to be allergic or intolerant to any of the ingredients used in the study; * Patients with long-term chronic diarrhea, abdominal pain, constipation or other digestive tract diseases; patients with gastrointestinal symptoms before chemotherapy (≥grade 2 NCI-CTCAE, version 4.0); * Synchronously receive other treatments that may cause diarrhea, such as radiotherapy; * Patients who take drugs for microecological regulation of digestive tract such as Combined Bifidobacterium, ChangTai oral liquid, etc; * Patients take traditional Chinese medicine or antibiotics; * Unable to understand and sign the informed consent form; * participants in other clinical trials.