Although the high costs and dubious benefits of prohibitionist policies are well documented, it would not be useful to abandon present legal controls simply from frustration or a sense of defeat. Positive alternatives must be provided. A major objective of social policy is to find means by which to minimize health and safety risks at the lowest level of social costs. A challenge of the 1990's is to implement and test a comprehensive public health model for effective control of demand for illicit drugs. 2 notes and 75 references (Author abstract)