Drug-induced hemolytic anemias are neither common nor severe enough to be recognized since the hemolysis is mainly extravascular. However, many patients receive drugs, so the potential for a drug reaction exists, and this immune-mediated mechanism must be distinguished from other causes for anemia. Cephalosporins are the most frequent drugs implicated. Treatment consists of cessation of therapy with the drug because most cases are due to drug-dependent antibody formation. Nutrient deficiencies reduce marrow production, so reticulocytosis is unlikely. DIC is unlikely with a normal platelet count. Parvovirus infection may suppress erythropoiesis transiently in individuals with normal red cells but may precipitate an aplastic crisis in those with a hemoglobinopathy. Persons with abnormal red cells are likely to have a history of anemia. Hemoglobinopathies are not Coombs positive.