Donald Armstrong updates and expands his highly praised Free Radical and Antioxidant Protocols (Humana, 1998) with a collection of new and valuable methods for evaluating the pertubations in cell function resulting from increased oxidative stress. Presented in a user-friendly, step-by-step format, these readily reproducible techniques cover both free radical-derived and antioxidant biomarkers. The methodologies demonstrated include ELISA, HPLC, infrared spectroscopy, gas chromatography–mass spectroscopy, immunoblotting, electroelution fractionation, isoelectric focusing, voltametry, and electron paramagnetic resonance imaging. Special emphasis is given to the separation of complex mixtures of plant antioxidants, soft drug design to protect from toxic oxidative metabolites, in vitro oxidation conditions, and correcting for random measurement error to improve statistical interpretation. A soon-to-be-published companion volume, Oxidants and Antioxidants: Ultrastructural and Molecular Biology Protocols (0-89603-851-3), contains state-of-the-art molecular and ultrastructural methods that expand the total number of protocols to 109 assays.