Marked rises are evident in reported Australian suicide rates since 1955. The changes since 1960 are due to greatly increased numbers of reported suicides by self-poisoning with drugs; there is also strong evidence that this category of suicide is subject to serious under-reporting probably to a greater extent than suicide by other methods. In the period 1960 to 1967, greatly increased quantities of sedative drugs were made available to the community. The contention that the concomitant rises in ready availability of sedatives and rates of drug suicides are causally related receives added confirmation from the observation of a decline in drug suicide following restricted prescribing of sedatives in Australia since July 1967. The data indicate the relevance of social factors to the problem of suicide and the need for control of sedative availability as a preventive measure.