Serum gamma-glutamyltransferasis activity is a low-cost, highly sensitive laboratory test. Though it is currently considered as an index of hepato-biliary dysfunction and alcohol abuse, recent epidemiological and pathologic studies have proposed its independent role in the pathogenesis and clinical evolution of cardiovascular diseases brought by atherosclerosis, associated with a gamma-glutamyltransferase-linked prooxidant effect of glutathione catabolism within the plaque.