Objective: In the present study, the antigenotoxic effect of disulfide compounds from Ferula persica on DNA damage in healthy rat lymphocytes induced by H2O2 was evaluated using single-cell electrophoresis (Comet assay). Sulfur containing compounds previously reported from F. persica, were persica sulfide A (PSA) and persica sulfide B (PSB). In our study two sulfur containing compounds were extracted and characterized by NMR. These two compounds were then identified as PSA and a new compound that after characterization was named persica sulfide C (PSC). Since the amount of extracted PSC was insufficient for comet assay, the antioxidant/antigenotoxic effects of PSA was investigated alone. Materials and Methods: Effect of solutions containing 1, 10, 50, 100, 200, 300, 400 and 500 μM of PSA, these concentration and 250, 500, 750, 1000 µM of ascorbic acid in the presence of hydrogen peroxide (H2O2) 25μM and 25, 50, 100 and 200 μM of H2O2 was tested on lymphocytes derived from the blood of healthy male Wistar rats (250-300 g), were measured by comet assay. The degree of damage to DNA after exposure to different solutions at 4° for 15 minutes was calculated based the amount of DNA present in the tail compared to the total amounts of lymphocyte DNA. Results: The results indicated that PSA did not have genetoxicity. And also it made a 50% reduction in DNA damage caused by H2O2 (EC 50) at the concentration 476.47 (360.28-630.13) μM. According to the calculated EC 50 for ascorbic acid [1399.23 (1054.27-1857.07)], it can be deduced that PSA is more potent than ascorbic acid in reduction of oxidative DNA damages Conclusion: It is concluted that PSA did not have genetoxicityeffect and prevented the oxidative DNA damage to rat lymphocytes. .