Three patients who, developed perianal complications in the course of acute leukemia, are described. The first case presented a successful cure of huge perianal ulcer. It was considered that an early improvement of neutrophil count and an adequate anal hygene by using a toilet stool equipped with a washer and by a sitz bath with 0.02% chlorhexidine digluconate had contributed to this cure of the ulcer. The second case demonstrated a rapid progression of perianal infection during a period of severe neutropenia below 100/cmm resulting in a prompt death of the patient. The delayed improvement of neutrophils and hypogammaglobulinemia were considered to be responsible for this result. The third case was a patient with an acute leukemia complicated by an anal fissure. In spite of her severe neutropenia during the remission induction, perianal deep infection was successfully avoided by the local hygene. Therefore, we assume that a perianal hygene is essential to prevent this kind of infection. Adequate administration of antimicrobial agents are required as soon as the infection is suspected. Surgical incision may be indicated when the abscess becomes fluctuant. So an improvement of neutrophils is necessary for the cure of this infection. Combination chemotherapy with DOAP (daunorubicin, vincristine, cytosine arabinoside and prednisolone) delayed but not interrupted the improvement of ulcer. Thus the treatment against leukemia should be performed without hesitation, even if the patient has a perianal infection, as long as an improvement of neutrophil count is expected to some extent.
