Functionally, genes provide the information that governs the basic biological and physiological activities of cells conditioning our behavior in relationship with our environment changes. CYP2A6 variants variably inhibit and reduce nicotine dependence and play an important role in nicotine uptake, distribution, and clearance, implying their clinical potential. Also, CYP2A6 variants have been linked to smoking behavior, nicotine-dependence development and treatment in epidemiological quantitative and human laboratory studies. It appears in this current study that CYP2A6 variants' enzymatic activities are correlated to variation in smoking behaviors, and are implicated in nicotine treatments as they are capable of metabolizing nicotine, and medication use in nicotine addiction treatment.