The goal of this single-arm trial is to learn if Fecal Microbiota Transplantation (FMT) works to treat hemorrhagic radiation-induced proctopathy. The main questions it aims to answer are:

• Dose FMT alleviate the symptom of severe rectal bleeding?
• Dose FMT improve the endoscopic findings of proctopathy?

Participants will:

• Take fecal microbiota capsules by 8 sessions over a 12-week period.
• Visit the clinic once every 4 weeks for checkups and tests.
• Keep a diary of their symptoms and the number of times they use other supportive care.

Inclusion Criteria:

• Age: 18-75 years old
• At least 3 months since the completion of pelvic radiotherapy
• No evidence of tumor recurrence or metastasis
• Rectal bleeding with grade 2-4 by LENT-SOMA scales
• Colonoscopy indicating rectal congested mucosa or telangiectasia
• Poor response to supportive care, or hemoglobin level less than or equal to 70 g/L in the past 3 months

Exclusion Criteria:

• Acute or chronic infectious diseases
• Serious systemic diseases
• Known allergies to any components of the study medication
• Colonoscopy indicating rectal ulceration (>1cm2), fistula, stricture, or necrosis
• Late complications related to pelvic radiation injury
• Other hemorrhagic or coagulation disorders
• Previous rectal resection
• Bowel obstruction or perforation that require surgery
• Cognitive or psychological disorder
• Contraindications to FMT administration