Patients with acute monocytic leukaemia are prone to perianal infections and should therefore be checked perianally. The presence of a large number of leukaemia cells infiltrating the patient’s body leads to the destruction of the immune system and a decrease in immunity. This, coupled with the effect of chemotherapy drugs on bone marrow suppression, results in a lack of granulocytes, which can easily lead to infections in various areas, while the perianal area is relatively hidden, moist and prone to bacterial growth, and can easily be damaged during constipation, leading to perianal infections.