Sixty subjects were run in a study comparing the use of nicotine gum with placebo gum during cessation from smoking. Subjects were given clinic support and chewed the gum ad libitum. A survival analysis showed the two groups differed significantly in successful abstinence over time (p less than .03). Differences between groups appeared early (within weeks) and, at six months, a 28% superiority of nicotine over placebo gum was demonstrated with mean success rates of 48% and 20%, respectively. Between six months and one year, relapse in the nicotine group accounted for the 30% vs. 20% success rates for nicotine and placebo observed at one year. In a pilot study ("dispensary") testing the efficacy of the two gums when intervention was minimal, subjects in both groups resumed smoking within the first two weeks. The enhanced short-term success rates with nicotine gum in the clinic study are attributed to an effective interaction between use of the active preparation and clinic support. Long-term cessation may require extended maintenance procedures and/or an identification of optimal gum use.