The purpose of this study is to determine if changing the timeframe (relative to cue presentation) at which the nicotine lozenge is given can attenuate the increase in symptoms of tobacco craving and withdrawal that occur when smokers are presented with smoking cues. In this cross-over study, all subjects attend three laboratory sessions at which either nicotine lozenge or placebo is given prior to presentation of smoking cues or after presentation of smoking cues. The order in which the three conditions will be presented are randomized.