Abstract
Cephalosporins are commonly used drugs that interact with red blood cell membranes. They frequently cause a positive direct antiglobulin test but rarely cause hemolysis. A case of cefotetan‐induced hemolytic anemia is described in which two types of antibodies were detected. One reacted with red blood cells by a hapten mechanism, the other reacted with drug to form immune complexes. This case is compared with the 13 cases of cephalosporin‐induced hemolytic anemia reported to date. Understanding the interactions of red blood cells and cephalosporins is critical to the safe use of these commonly prescribed drugs.