Lisinopril is an inhibitor of the renin-angiotensin system. Does lisinopril minimize oxidative damage in spontaneously hypertensive rats (SHR) in comparison with the normotensive genetic controls Wistar Kyoto (WKY)? The authors note that lisinopril contained lipid peroxidation, elevated tissue glutathione levels, and influenced the activity of antioxidant enzymes such as catalase and glutathione peroxidase. Studies in humans testing the hypothesis that lisinopril has antioxidant function in vivo are warranted.