Naringenin has been shown to exert antiestrogenic, cholesterol-lowering and antioxidant activities, as well as an indirect modulation on the metabolism of many xenobiotics. It is one of the most abundant polyphenols in tomato. Given the widespread consumption of tomato (Lycopersicum esculentum) and tomato-based products, this study was designed to determine whether plasma levels of naringenin were detectable in five men after consumption of a test meal containing 150 mg of cooked tomato paste. Naringenin intake with the test meal was 3.8 mg. Blood was drawn from fasting subjects and 2, 4, 6, 8 and 24 h after the meal. To compare the results with a control, the same meal without tomato paste (control meal) was administered to the same subjects 2 wk later. Analyses were performed using high-performance liquid chromatography coupled with a CoulArray electrochemical detector. The peak plasma concentration was 0.12 +/- 0.03 micro mol/L 2 h after the meal. Unconjugated naringenin was not detected. Naringenin was not detected in plasma at any time after consumption of the control meal. In addition to naringenin, we detected rutin and chlorogenic acid in tomato paste, but these polyphenols and their derivatives (quercetin and caffeic acid) were not detected in plasma at any time. To the best of our knowledge, this is the first study demonstrating naringenin bioavailability in humans after consumption of a meal containing cooked tomato paste.