To examine (a) numbers of alcohol and drug-related hospital separations, 1999-2005; (b) demographics of these separations; (c) principal diagnoses co-occurring with drug-related problems; (d) length of hospital stay.

Data from the National Hospital Morbidity Database (NHMD) were analysed. Hospital separations where alcohol, opioids, amphetamine, cannabis, cocaine, other drugs (such as sedatives and hypnotics) and pharmaceutical poisoning were mentioned were examined.

Numbers per million persons were highest for alcohol, followed by other drugs, particularly sedatives and hypnotics. Alcohol and opioid-related problems were prominent among older age groups, whereas cannabis and pharmaceutical poisoning problems had greater proportions among 15-24 year olds. Opioid-related separations were relatively high in number within the context of prevalence of use, and often accompanied by principal diagnoses of physical or general health problems. Almost half of amphetamine and cannabis-related separations were accompanied by principal diagnoses of mental health problems.

This research highlights the complexities of drug-related hospital presentations, indicating the need for thorough assessment of physical and mental problems, as well as a drug use history at the time of admission. Continued development of integrated models of care, targeting both mental health and drug use are essential. Consistent with the international literature, many of these separations are preventable, particularly those for pharmaceutical poisoning. Finally, ongoing efforts to reduce the significantly greater harms related to opioid use, as well as increasing treatment opportunities for opioid-dependent people in Australia is an important public health priority.