In this study, the effects of the common herbicide 2,4-D (dichlorophenoxyacetic acid) on blood antioxidant / oxidant status and on various organs were investigated in Sakiz crossbred lambs. For that, 6 lambs were poisoned accidentally with the herbicide whereas 6 other healthy animals served as negative controls and plasma MDA and GSH concentrations as well as serum ascorbate, retinol and beta-carotene concentrations were determined by spectrophotometry two days later. In parallel, conventional histological analysis was performed on lungs, liver, kidney and heart front a lamb dead after 2,4-D exposure. Blood antioxidant/oxidant balance was altered due to a significant increase of MDA concentrations coupled to a significant decrease of GSH concentrations in intoxicated lambs compared to controls. Congestive lesions and some haemorrhages were evidenced in lungs and kidneys and cell degeneration associated with lymphocyte infiltrate were observed in liver, kidneys and in heart. These results highly suggest that the herbicide 2.4-D induces an oxidative stress leading to cell destructions and tissue injury.