1病例介绍患者女,67岁。因直肠癌术后3个月伴下消化道出血半个月入院。患者入院前3个月因肠镜活检诊断为直肠癌而入院行直肠癌低位切除术,术中未发现肿瘤扩散及转移,行根治术后恢复可,术后2周出院。患者半个月前出现暗红色血便, 1 case description Female patient, 67 years old. Due to rectal cancer after 3 months with gastrointestinal bleeding half a month admitted. Three months before admission, the patient was diagnosed with colorectal cancer by colonoscopy biopsy and admitted to the hospital for rectal cancer low resection. No tumor spread and metastasis was found during operation. The patients were cured after radical operation and discharged after 2 weeks. Dark red bloody stool appeared in patients two weeks ago,