Oxidative stress plays a crucial rote in a variety of clinical settings of atherogenesis, and mediates many pathways linked to atherosclerosis and inflammation. gamma-Glutamyttransferase (GGT), an enzyme responsible for the extracellular catabolism of antioxidant glutathione, may directly take part in atherogenesis and evolve as a potential biochemical risk indicator of cardiovascular morbidity and mortality. Classically, GGT has been thought of as a diagnostic tool for hepatobiliary disorders and alcohol abuse. More recently, growing body of data points out that serum GGT levels can aid detection of individuals at high risk for subsequent cardiovascular events, and thus have an application in primary and secondary prevention of cardiovascular disease. Although several investigations have shown that some drugs are effective in decreasing both serum lipids and GGT, and concomitantly the incidence of subsequent cardiovascular events; large-scale randomized trials are required to explore this impact directly. Based on current experimental and epidemiological studies, we postulate here that GGT present in the serum, even within its laboratory reference intervals regarded as physiologically normal, is a promising biomarker for cardiovascular risk. (c) 2006 Elsevier Ltd. All rights reserved.