We evaluated in human endothelial cells in culture the effect of l-carnitine (C), acetyl-l-carnitine (AC) and propionyl-l-carnitine (PC) on gene and protein expression (RT-PCR and Western blot) of oxidative stress related proteins heme oxygenase-1 (HO-1) and of endothelial NO synthase (ecNOS) in absence and presence of oxidative stress induced by H2O2.