Purpose: To determine the effectiveness of the 4-mg and 2-mg dosages of nicotine polacrilex vs placebo through the first 6 weeks of treatment (during which 75% of relapse occurs when there is no treatment) in assisting high-dependent smokers to stop smoking when instructed to use a fixed number (12 pieces) of medication daily. Subjects and Methods: Ninety high-dependent (Fagerstrom Tolerance Questionnaire score greater than or equal to 7 plus baseline carbon monoxide level > 15 ppm) healthy male and female smokers, highly motivated to quit smoking, were enrolled in a 6-week, randomized, double-blind, placebo-controlled trial in which they were instructed to use 12 pieces per day of their assigned dosage formulation: 4 mg, 2 mg, or 0.5 mg (placebo) of nicotine polacrilex. The behavioral intervention did not depend on providing any special psychological training, skills, or services but rather employed a standard medical practice model that could easily be implemented by any primary care physician. Results: Sustained abstinence from weeks 2 through 6, determined at each visit by absolutely no cigarette use plus a carbon monoxide level of 8 ppm or lower was 59% (4-mg group), 30% (2-mg group), and 39% (placebo group) (P<.02). For the 55 of the 90 smokers who met the originally planned definition of high dependence (Fagerstrom Tolerance Questionnaire score greater than or equal to 7 plus baseline smoking serum cotinine level >250 ng/ml plus baseline carbon monoxide level >15 ppm), results were 63% (4-mg group), 25% (2-mg group), and 25% (placebo group) (P<.02). In addition, the 4-mg dose produced statistically significantly higher abstinence rates in compliant subjects (P<.02) and also in subjects with high baseline serum cotinine levels who were compliant (P<.01) than did either the 2-mg dose or placebo. Conclusions: It appears that the 4-mg dose of nicotine polacrilex is the drug and dose of choice for the initial phase of tobacco dependence treatment in high-dependent smokers; the 2-mg dose of nicotine polacrilex is no better than placebo during the first 6 weeks of treatment for high-dependent cigarette smokers, and thus should not be used for these patients during the initial treatment phase.