A.P., a 42-year-old woman, presented with rectal bleeding to her primary care physician. Endoscopic examination revealed a mass in the anal canal. Biopsy was positive for squamous cell carcinoma. A.P. underwent local excision and was established as stage ii (T2n0m0). After surgery, she received 5-fluorouracil (Fu) 1,000 mg/m by continuous infusion on days 1–4 and on days 29–32, mitomycin-c 10 mg/m days 1 and 29, and radiation therapy (4c500 cgy). minimal nausea was the only side effect. A.P. achieved complete remission. Approximately eight weeks after completing therapy, A.P. presented for an implantable port flush. The nurse noted that A.P. was pale, weak, and short of breath. A complete blood count (cBc) was obtained and revealed a hematocrit of 17.1% (normal range 37%–48%), hemoglobin of 4.9 (normal range 12.3–15.3 g/dl), and platelet count of 50,000 (normal range 150,000–450,000 cells/ml). A physical examination revealed paleness with generalized anasarca. A.P. was afebrile; her blood pressure was 180/100 mm Hg, pulse rate was 72, and respiration was 24. A.P. was admitted to the hospital for further evaluation and possible blood transfusion. Other laboratory results included a serum creatinine 3.5 mg/dl (normal range 0.7–1.4 mg/dl), lactic dehydrogenase (lDH) 342 units/l (normal range 140–280 units/l), and serum haptoglobin < 38 mg/dl (normal range Hemolytic Uremic Syndrome