This report presents the findings of the South Australian component of a national investigation into the heroin shortage which began in early 2001. The report finds that within the first few months of the shortage in South Australia, the availability of heroin was severely restricted and what could be sourced was of very low purity. At the present time heroin can be acquired on demand though not as easily as before the shortage, while the purity of street level heroin has slowly increased. The report examines the South Australian impacts of the heroin shortage in terms of changes in the drug market; changes in patterns of drug use; health related impacts; changes in treatment provision for drug based issues; changes in criminal activity; and impacts on health and law enforcement agencies. The analysis finds that following the heroin shortage there was a reduction in the number of fatal and non fatal heroin related overdoses and a reduction in heroin use; greater methamphetamine use; intravenous use of benzodiazepines and other opioids; an increase in mental health difficulties, psychosis and violence due to increased methamphetamine use, as reported by key informants, though this was not reflected in hospital data; no significant increase in treatment seeking for opioids, but a steady increase in the demand for methamphetamine related treatment services. With respect to crime, the report finds no changes in the rates of incidents per month that were probably attributable to the heroin shortage, apart from an initial spike in incidents of robbery without a weapon. (Executive summary, edited)