Harm reduction is a term well known to people working in the field of alcohol and other drugs. However, there is considerable diversity of opinion as to what the term should mean. The danger is that this confusion may drive the community to seek refuge in the more easily understood, but absolutist, prohibition and abstinence oriented responses to drug use. In this brief commentary a harm reduction program or policy is defined as one in which (1) the primary goal is to reduce net health, social and/or economic harm without necessarily seeking to reduce use, and (2) it can be directly demonstrated, against broadly agreed criteria, that net harm across a number of dimensions has been reduced, rather than by claiming or inferring from changes in other indices that harm has been reduced. It is concluded that those who claim that use reduction constitutes harm reduction need to establish that such an approach does actually result in an overall reduction in harm.