Abstract: 【】A female patient aged 58 years with acute tonsillitis was treated with cefoxitin 2.0g twice daily.The day after,patient had abdominal pain and dark red rash on whole body skin after intravenous drip cefoxitin about 30 min. Laboratory tests showed the following values:microscopically RBC 8-9 / HP, occult blood 1, urine sediment RBC 32 /μL.Then anaphylactoid purpura is diagnosed. The patient was immediately stoped using cefoxitin, and treated with chlorphenamine maleate,dexamethasone,calcium gluconate, ioratadine and prednisone acetate. The day after,dark red rash fades and abdominal pain disappears.The microscopic RBC 0-3/HP, occult blood -, urine sediment RBC 5 /μL.After a week, patients with dark red skin rashes completely disappear.