This study evaluated the effect of administration of exogenous antioxidant (antox) on the course and treatment of Trichinella spiralis in the intestinal phase (2 days post infection, p.i.) and the muscle phase (35 days p.i.) using albino rats as an experimental model. The results indicated that the administration of antox had led to delayed expulsion of adult worms from the small intestine, decreased inflammatory reactions in the intestines and muscles and causing an increase in the muscle larval burden. The intake of antioxidant decreased the efficacy of mebendazole on adult worms in the intestinai phase, while it enhanced the effect of treatment in the muscle phase and the number of larvae was highly decreased. So, antox inhibited free radical generation in small intestine which acts as a contributing factor to the rejection process. But, in muscle phase, the decreased inflammatory reaction around larvae increases the chance of the drug to reach larvae and affects them.