Following the introduction of black tar heroin mainly from Mexico in the 1980s, cases of wound botulism dramatically increased in the western United States. Contamination with spores of Clostridium botulinum of black tar heroin occurs along the distribution line. The heating of heroin powder to solubilize it for subcutaneous injection ("skin popping") does not kill the spores. The spores germinate in an anaerobic tissue environment and release botulinum toxin type A or B. Unless skin abscesses are found in the patient, the clinical diagnosis is often challenging. Facilitation of the compound muscle action potential by repetitive nerve stimulation at 20 to 50 Hz is an important and rapid diagnostic test. Definite diagnosis is made by detection of botulinum toxin in serum or isolation of C botulinum from the abscess. Early treatment with equine ABE botulinum antitoxin obtained from the Centers for Disease Control and Prevention often shortens the time on a ventilator.