This data was based on the most recent National Drug Strategy Household Survey, which was conducted in 1998. The survey included questions on personal experiences of heroin overdoses and reporting behaviors (whether overdoses were reported and, if not, reasons why). Results indicated that a significant proportion of overdose witnesses did not call for an ambulance or for other medical help. Reasons given included an unwillingness to get involved and fear of police involvement. The latter was attributable partly to fear of prosecution on drug charges or on outstanding warrants, and partly to witnesses’ concern over legal liability in the event of the user’s death. There was no general duty to provide or call for assistance, but such a duty may arise from particular circumstances or relationships. A duty of care may be breached by failure to call for assistance or by negligently administering assistance. However, the practical likelihood of criminal prosecution of a witness for the death of an injecting drug user is, in all but the most exceptional of circumstances, minimal. The appropriate public policy message is that the legal risks to overdose witnesses in calling for assistance are far outweighed by the medical risks to the user of not doing so. 3 tables and 23 references.