?The metabolic activation of many drugs and xenobiotics in vivo is effected through the large family of cytochrome P450s enzymes that catalyse a diverse spectrum of reactions including the metabolism of both endogenous and exogenous compounds. There is considerable evidence suggesting that changes in P450 activities can affect the in vivo toxicity of drugs in both animals and humans. Oxidative metabolism by cytochrome P450 enzymes has been implicated in the pathogenesis of cancer, through the formation of toxic intermediates and carcinogenic metabolites are formed from drugs and xenobiotics....