At present, there is still a lack of standard and effective treatment strategies and procedures for radiation intestinal injury. Studies have shown that thalidomide can effectively treat refractory gastrointestinal bleeding caused by vascular malformation. Therefore, The investigators designed a single-center, open-label, randomized controlled study to evaluate the efficacy and safety of thalidomide combined with glutamine in the treatment of radiation intestinal injury.

Screening: This phase will not last longer than one week, and the subject will be assessed for eligibility after signing the informed consent form.

Treatment: Subjects were randomly assigned to three different treatment groups for 8 weeks.

Follow-up: The subjects' defecation status was recorded every day during treatment, telephone follow-up was conducted every two weeks, and laboratory indicators (including blood routine, stool routine, etc.) were tested every four weeks. The test was terminated one week after treatment and the improvement of subjects' stool blood was assessed.

Inclusion Criteria:

• Age 18-80 years old, gender is not limited;
• Patients with hematochezia symptoms of chronic radiation intestinal injury: Due to the lack of diagnostic gold standard for radiation intestinal injury, a comprehensive analysis of clinical, endoscopic, imaging and histopathological findings was mainly performed to make the diagnosis of radiation intestinal injury on the basis of excluding infectious and other non-infectious intestinal injuries. Exposure to radioactive sources is a necessary factor in the diagnosis of radiation intestinal injury, and tumor activity or recurrence should be excluded.
• The proportion of dominant defecation bleeding in total defecation times in the week before treatment is not less than 20%;
• ECOG score: 0-2.

Exclusion Criteria:

• Patients with hemodynamic instability;
• Patients with obvious liver and kidney function injury: bilirubin, aminotransferase (ALT, AST) exceeded the upper limit of normal by 2 times; eGFR<60ml/min or dialysis patients;
• Patients allergic to thalidomide or glutamine;
• Patients whose primary disease was gastrointestinal malignancy;
• Patients currently suffering from serious or uncontrolled underlying diseases of the blood, digestive tract, metabolism, endocrine, lung, heart, nervous system, mental system, etc.;
• Female patients during pregnancy and breastfeeding (including patients with reproductive needs);
• Patients infected with HIV;
• Patients who cannot cooperate with regular follow-up and review of laboratory indicators;
• any other circumstances which, in the opinion of the investigator, would render the subject unfit for study inclusion.