The ability to process xenobiotica and many endogenous compounds is called biotransformation and is catalysed by enzymes mainly in the liver of higher organisms but also a number of other organs such as kidneys, gut and lungs. Metabolism occurs in two stages; phase 1 functionalisation and phase 2 conjugation. Defects in enzymes in these two phases can lead to disease (Nebert et al. 2013, Pikuleva & Waterman 2013, Zanger & Schwab 2013, Mudd 2013, Messenger et al. 2013, Aoyama & Nakaki 2013, Shih 2004, Millington 2013, Azimi et al. 2014, Sticova & Jirsa 2013).