阿米巴痢疾是由原虫埃安腊巴组织内阿米巴引起的寄生虫感染。有时，阿米巴痢疾在免疫抑制条件下，如化疗时可以激活。我们报告了一个由于无症状埃安腊巴组织内阿米巴感染，在胃癌化疗过程中被激活导致的急性阿米巴结肠炎的病例。患者在接受三个疗程的胃癌化疗后出现腹泻和发热，被诊断为急性肠炎。由于大便有血丝，进行了结肠镜检查和活检。组织病理学发现病原虫侵入了直肠。因此，患者被诊断为阿米巴结肠炎，并接受了甲硝唑治疗。由于怀疑肠穿孔，进行了紧急手术，术后患者的整体情况得到改善并出院。随后，进行了胃癌手术，患者出院时无术后并发症。因此，在癌症化疗期间出现结肠炎时，应将阿米巴结肠炎列为鉴别诊断，并进行结肠镜活检。© 2023. 日本消化系统学会。

Amoebiasis is a parasitic infection caused by the protozoan, Entamoeba histolytica. At times, amoebiasis is activated under immunosuppressive conditions such as chemotherapy. We report a case of fulminant amoebic colitis resulting from an asymptomatic Entamoeba histolytica infection, which was activated by chemotherapy for gastric cancer. The patient developed diarrhea and fever after three courses of chemotherapy for gastric cancer and was diagnosed with acute enteritis. A colonoscopy and biopsy were performed because of the bloody stool. Histopathological findings revealed amoebic invasion of the rectum. Therefore, the patient was diagnosed with amoebic colitis and was treated with metronidazole. Emergency surgery was performed because intestinal perforation was suspected after which his general condition improved and was discharged. Subsequently, gastric cancer surgery was performed and the patient was discharged without postoperative complications. Hence, amoebic colitis should be listed as a differential diagnosis, and a colonoscopic biopsy should be performed when colitis occurs during chemotherapy for cancer.© 2023. Japanese Society of Gastroenterology.