We describe the case of a 54-year old woman with breast cancer who was treated by vancomycin for febrile neutropenia due to a methicillin-resistant Staphyloccocus epidermidis infection of a surgically implanted catheter. She developed an hypersensitivity reaction to vancomycin associating neutropenia, fever, skin rash and elevated liver enzymes following re-challenge with vancomycin after having been misdiagnosed with septic thrombophlebitis. Following this re-challenge, neutrophils count fell dramatically but promptly resolved after cessation of vancomycin.