The objective of this book was to clinically evaluate the effectiveness, color stability, tooth sensitivity, and genotoxicity of home whitening with 10% carbamide peroxide (CP) in smokers and non-smokers. Teeth whitening was performed with 10% CP (Whiteness Perfect - FGM, Joinville, Santa Catarina, Brazil) for 3 hours daily for three weeks. Color was evaluated using the Vita classical scale, Vita Bleachedguide 3D-MASTER, and Vita Easyshade spectrophotometer (Vita Zahnfabrik, Bad Säckingen, Germany), initially during teeth whitening (1st, 2nd, and 3rd weeks) and after this procedure (1 week and 1 month). Tooth sensitivity was recorded by the patients themselves using a 0-4 scale and a 10 cm visual analog scale (VAS). The genotoxicity of whitening was assessed by the frequency of micronuclei (MN) in the gingival tissue before and after whitening.