Nicotine influences many risk factors for cardiovascular disease, peptic ulcer disease, pregnancy complications and wound healing; however, whether nicotine itself actually causes or aggravates these diseases has not been well demonstrated. The safety of nicotine preparations for smoking cessation depends on the population, formulation, route of administration, dose, and frequency and duration of use. Major adverse effects of nicotine polacrilex and transdermal nicotine are very rare. Nicotine therapy usually doubles long term abstinence rates and is especially beneficial to highly dependent smokers. Nicotine replacements produce lower nicotine concentrations than cigarettes, and no tar and carbon monoxide; thus, it is difficult to justify absolute contraindications to these products. Decisions on the use of nicotine preparations in pregnancy, coronary disease, etc., must consider not only the medical status of patients but also their likelihood of stopping smoking with and without the help of nicotine replacement.