Hydrogen has been reported as a novel antioxidant to selectively reduce levels of toxic reactive-oxygen species (ROS). We investigated the effects of hydrogen-rich saline on the prevention of oxidative injuries in N(omega)-nitro-L-arginine methyl ester (L-NAME) induced rat model of preeclampsia (PE). Sprague-Dawley rats (n = 50) were randomized into five groups: non-pregnant; normal pregnancy; pregnancy + hydrogen saline, 5 ml/kg, intraperitoneal (i.p.); pregnancy + L-NAME, 60 mg/kg (i.p.); pregnancy + L-NAME + hydrogen saline rats. Terminations of pregnancy were performed on day 22 of gestation, when the placentas and kidneys were microscopically inspected; tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and malonyldialdehyde (MDA) were assessed; and the mean systolic BP, level of proteinuria, resorptions, and pups birth weights were recorded. It was found that the pups of hypertensive gravid rats treated with hydrogen-rich saline presented fewer number of resorptions than those of the group of pregnancy + L-NAME, 60 mg/kg i.p. (P < 0.05). Additionally, hydrogen-rich saline treatment decreased the blood and placental MDA, proteinuria and the pro-inflammatory cytokine TNF-α, IL-1β in the placental tissues compared with those in L-NAME-treated rats (all P < 0.05). The mean systolic BP showed no significant difference except on day 22 of gestation (P < 0.05). The preventive administration of hydrogen significantly attenuated the severity of PE, which might be ascribed to a reduction in inflammation response and oxidative stress. It could be concluded that hydrogen can be an effective antioxidant in the management of PE.