Potential subjects who have abused alcohol or drugs, or have used within the last 30 days experimental (investigational) drugs, psychiatric medications (including antidepressants, anti-psychotics) or any other medications that are known to affect smoking cessation (e.g. clonidine) will be excluded. Potential subjects who have used smokeless tobacco (chewing tobacco, snuff), cigars, pipes, nicotine replacement therapy, or other smoking cessation treatment within the last 2 weeks will be excluded. Pregnant or nursing mothers will be excluded.