Clostridium novyi has been associated with a large outbreak of severe infections in injection drug users. A case of bacteraemia with Clostridium butyricum in an injection drug user is reported. During treatment for Staphylococcus aureus osteomyelitis, the patient used an indwelling central venous catheter to inject cocaine. He was admitted with C. butyricum sepsis that responded to broad spectrum antibiotics, including vancomycin. Local investigation for other cases was unrevealing; however, growth of an unusual pathogen in clinical specimens should be investigated as it may represent a sentinel event with public health implications.