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 (BHT) 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, data interpretation of complex mixtures, and collaborative work.