Evaluation of the clinical efficacy and safety of a nicotine 2-mg sublingual tablet in smoking cessation. A randomized, double-blind, placebo-controlled study of smokers using the 2-mg tablet for 3-6 months with follow-up to 12 months. Dosing was established according to baseline nicotine dependence, scored on the Fagerström Tolerance Questionnaire (FTQ): FTQ > or = 7, two tablets/hour (maximum 40/day); FTQ < 7, one tablet/hour (maximum 20/day). Smoking cessation programme in a department of oral and maxillofacial surgery. A total of 247 adult smokers, smoking > or = 10 cigarettes/day for > or = 3 years, of whom 123 received active and 124 placebo treatment. The study was powered to detect difference at 6 months. Efficacy and safety were evaluated at 6 weeks and 3, 6 and 12 months. Self-reported abstinence was verified by exhaled CO < 10 p.p.m. Success rates for complete abstinence (no slips after 2 weeks) for active vs. placebo were 50% vs. 29% at 6 weeks, 42% vs. 23% at 3 months, 33% vs. 18% at 6 months and 23% vs. 15% at 12 months (p < 0.001, 0.001, 0.005 and p = 0.14), respectively. Craving during the first 8 days was significantly reduced among highly dependent smokers on active treatment compared to placebo. Baseline mucosal lesions among abstinent subjects were reduced during the treatment period and at the non-treatment follow-up. Adverse events were mild and tolerable, the most common being irritation and soreness in the mouth and throat. The nicotine sublingual tablet increased the smoking cessation rate compared to placebo, reduced craving in highly dependent smokers and was well tolerated.