Harm reduction, an alternative to both drug legalization and drug prohibition, seeks to preserve prohibition by keeping the supply of drugs illegal while softening some of the harsh consequences of prohibition. Typical harm reduction proposals are needle exchanges for intravenous drug users to reduce the spread of HIV infection and the medical use of marijuana for a variety of illnesses including AIDS, glaucoma, multiple sclerosis, and cancer chemotherapy-induced nausea and vomiting. While attractive as a reasonable-sounding compromise, harm reduction carries a high price because it undermines the social signal of prohibition. This signal is a vital public health strategy, especially when it comes to primary prevention of use of alcohol and other drugs by youth. A personal experience with harm reduction, leading to rejection of this approach, is described. Harm reduction, enjoying a minor comeback in the United States, is a favored policy in much of Europe today. Harm reduction is not new, and it is a failure as a public health policy.