The substance methadone is used for substitution therapy since the 1960s in the U.S. Mainly because of the endemic spread of HIV-1 infections among intravenous drug abusers methadone was made legally available through medical prescription in Austria in 1987. Legal authorities today also allow the patient to take home the necessary daily consumption for weekends or public holidays. The drug is distributed as a watery solution in tiny bottles, which are fitted with an ordinary screw cap. This kind of distribution may, however, have fatal consequences. This is demonstrated in the following case of accidental poisoning of an infant: A two-year-old girl whose parents were both participating in the substitution scheme was found dead in her bed in Vienna in 1997. Forensic autopsy revealed a methadone concentration in the liver tissue of 640 ng/g. The criminal investigation determined that the girl had opened a bottle of methadone solution and subsequently had taken the drug. Considering the circumstances of this accident, from the medical point of view safety devices for the screw caps of the methadone bottles should be required by law, in order to avoid future accidental poisoning.