The Surgeon General of the United States concluded in 1988 that the nicotine in cigarette smoke is an addictive drug. This column reports on an experiment which revealed that smokers, when confronted with warnings that were repugnant and threatening to many of them, could still make choices consistent with the widely accepted standard rules of rational choice. The model of the two-self economic man offers one explanation for how the participants could engage in such apparently rational behaviour in the face of their addiction.