Alpha-lipoic acid (${alpha}$-LA) is not only involved in energy metabolism, but is also a powerful antioxidant that can protect against hepatic oxidative stress induced by some drugs, toxins, or under various physiological and pathophysiological conditions. Here, we investigated the effect of ${alpha}$-LA against liver oxidative damage in broilers exposed to aflatoxin $B_1$ ($AFB_1$). Birds were randomly divided into four groups and assigned different diets: basal diet, 300 mg/kg ${alpha}$-LA supplementation in basal diet, diet containing 74 ${mu}g/kg$ $AFB_1$, and 300 mg/kg ${alpha}$-LA supplementation in diet containing 74 ${mu}g/kg$ $AFB_1$, for 3 weeks. The results revealed that the addition of 300 mg/kg ${alpha}$-LA protected against the liver function damage of broilers induced by chronic low dose of $AFB_1$ as estimated by a significant (p<0.05) change in levels of plasma total protein, albumin, alkaline phosphatase and the activities of liver glutamic-oxalacetic transaminase and glutamic-pyruvic transaminase. The histopathological analysis also showed that liver tissues were injured in the $AFB_1$ diet, but this effect was alleviated by the addition of 300 mg/kg ${alpha}$-LA. Additionally, $AFB_1$ induced a profound elevation of oxidative stress in birds, as indicated by an increase in malondialdehyde level, a decrease in glutathione peroxidase activity and a depletion of the glutathione content in the liver. All of these negative effects were inhibited by treatment with ${alpha}$-LA. Our results suggest that the inhibition of $AFB_1$-induced excess production of lipid peroxides and the maintenance of intracellular antioxidant status may play important roles in the protective effects of ${alpha}$-LA against $AFB_1$-induced oxidative damage in the liver.