The method described in this book quantifies simultaneously four main products of lipid and protein peroxidation; free malondialdehyde, protein-bound malondialdehyde, and total lipid and protein hydroperoxides. The method is fast, simple and very sensitive, and its multi parametric nature permits the study of the interrelationship of the lipid and protein peroxidation processes in a more comprehensive manner than with the traditional single-parametric methods. The method can be applied in basic biological research, and especially in the clinical research concerning human disease.