Nicotine replacement therapies (NRT) have proven efficacy to help smokers quit. However, their effectiveness is low. This study aims to answer the question: Does the dose adjustment of NRT according the saliva concentration of nicotine's main metabolite: cotinine improve their efficacy compared with the lack of dose adjustment (usual care) in smoking patients with smoking related disease condition.

Smokers currently smoking at least 10 cigarettes per day with smoking related diseases are included. They are randomized either to receive standard nicotine replacement therapy (24 h nicotine patch 21, 14, 7 mg/day for one month each, respectively), control arm, or nicotine dose adjustment according their saliva cotinine: dose adaptation arm. In the control arm, at the discretion of the investigators, buccal forms of nicotine replacement therapies are allowed. In both arms, saliva cotinine determinations are performed every 2 weeks for 2 months. In the control arm saliva cotinine results are not communicated to the investigators. In the dose adaptation arm investigators receive saliva cotinine results and should adapt the nicotine doses (mg of nicotine/day) according to baseline (when smoking) saliva cotinine to obtain 100 % substitution. Smokers are assessed at weekly visits after the predetermined quit day for 3 months. Follow up at 6 months. Main outcome measure: sustained abstinence (self reported no smoking and expired air carbon monoxide concentration equal or less than 8 ppm during the last (3rd) month of the treatment phase.

Inclusion Criteria:

• Age ≥18 years Smoking ≥ 10 cigarettes per day Patients with disease conditions known to be related to smoking: e.g.coronary heart diseases, COPD, lower extremity arterial disease, etc

Exclusion Criteria:

• Smokers whose follow-up during the duration of the study, in a predictable way, cannot be assured.
• smokers having been treated by bupropion ( Zyban) during two months preceding the inclusion
• persons under TSN, neuroleptic, substitute treatments in OPINOIDES, under anticoagulants-non-equilibrating,
• encircled woman
• breast-feeding woman
• Contraindication usual of the TSN