 The main objective of this study is to compare the biomarkers of exposure to cigarette smoke constituents in smokers switching to SMAR and to biomarkers in smokers of conventional cigarettes CC. The biomarkers of exposure will be measured in blood and urine samples collected from the subjects. Moreover, the biomarkers in subjects smoking conventional or SMAR cigarettes will be compared with those biomarkers in smokers who stop smoking for 5 days. The short term safety of this new product will also be evaluated. 