A laboratory experiment is described to provide students hands-on experience in learning some aspects of microsomal P450-catalyzed metabolism. Undergraduate students in the biochemistry laboratories detect and quantify the metabolites produced from butylated hydroxytoluene by liver microsomes using Gas Chromatography-Mass Spectrometry (GC-MS) techniques. The laboratory provides training to students for handling active microsomes, sample cleanup of biological matrices, extraction of organic metabolites, GC-MS analysis and data interpretation of complex mixtures, and collaborative work.