A nicotine gum has been approved as a prescription drug to help smokers stop smoking. This article reviews the rationale, pharmacology, efficacy, adverse effects, and method of use of the gum. Several randomized trials, including double-blind placebo-controlled studies, indicate nicotine gum improves long-term quit rates. The efficacy of the gum seems to be due to its ability to relieve withdrawal symptoms. Successful use of the gum depends on appropriate instructions, expectancies, and adjunct therapies. How effective the gum will be when used in general medical practice, to whom it is best to prescribe the gum, and what proportion of smokers will become dependent on the gum are still unclear.