We report a case of a brainstem infarction and hemorrhage seen in a 21-year-old female with systemic lupus erythematosus (SLE) during treating retroperitoneal abscess. SLE has been treated with prednisolone and mizoribine for 4 years. The patient with right back and lower abdominal pain visited our hospital. Computed tomography (CT) revealed retroperitoneal abscess over surrounding right kidney, horizontal part of duodenum and in front of psoas muscle. Drainage was done with indwelled right single J catheter and penrose drain. Retroperitoneal abscess was much smaller, but, post drainage day 17, high fever, unconsciousness, down-blood pressure and down-beat nystagmus appeared suddenly. Brain CT scan revealed a brainstem wide infarction and hemorrhage spot. Pulse therapy with steroid was done, however unfortunately the patient was dead after 6 days.