Medicinal preparations based on sea buckthorn (SBT), a medicinal plant, have been clinically used to treat different diseases. We have developed a dietary additive based on SBT, the effect of which was evaluated against hexachlorocyclohexane (HCH), which was used to induce oxidative stress and toxicity in rats. Six groups of six male rats each were maintained for 12 weeks as (a) Control, (b) HCH, (c) 1% SBT based herbal formulation (SHF) incorporated diet, (d) 1% SHF incorporated diet + HCH, (e) 2% SHF incorporated diet, and (f) 2% SHF incorporated diet + HCH. Results revealed that HCH induction resulted in a significant hepatic lipid peroxidation with reduction in antioxidants and activities of antioxidant enzymes. The prefeeding of SHF resulted in decreased hepatic levels of lipid peroxides and increased the multicomponent antioxidant system namely glutathione (GSH), GSH-peroxidase, GSH-reductase, superoxide dismutase, catalase, and GSH S-transferase activities. The study suggests that HCH induction resulted in free radicals, which could be reduced by the incorporation of the herbal formulation in diet.