BACKGROUND: Tongue tumors, which are oropharyngeal tumors, are increasing in frequency. Pyrrolidine dithiocarbamate (PDTC) is a powerful antioxidant and antitumoral agent. OBJECTIVES: To evaluate the protective and therapeutic effects of PDTC in a tongue cancer model induced with 4-nitroquinoline 1-oxide (4-NQO). MATERIAL AND METHODS: We included 40 rats in the trial and assigned them randomly to 5 groups. Group 1 (cancer, n = 7): 4-NQO (0-12 weeks); group 2 (protection, n = 8): 4-NQO (0-12 weeks) + PDTC (300 mg/kg/day, 0-12 weeks); group 3 (therapy-high dose, n = 10): 4-NQO (0-12 weeks) + PDTC (600 mg/kg/day, weeks 12-30); group 4 (therapy-low dose, n = 10): 4-NQO (0-12 weeks) + PDTC (300 mg/kg/day, weeks 12-30); and group 5 (control). Cardiac blood samples were taken to analyze oxidative stress parameters (total antioxidant status (TAS), total oxidant status (TOS) and oxidative stress index (OSI)). Histopathological assessment was performed under a light microscope. RESULTS: The results of the histopathological assessment showed that the model we used in group 1 was successful, which was consistent with the literature. The PDTC dose administered in group 2 could not prevent tumor formation. Group 3 demonstrated that PDTC in high doses is effective as a therapeutic agent. Group 4 indicated that PDTC in low doses has no therapeutic effect. The results of the biochemical assessment showed that in group 3, TOS and OSI values were significantly lower than in groups 1, 2 and 4. No significant difference was found in the TOS and OSI values between groups 5 and 3. CONCLUSIONS: Our study demonstrated histopathologically that in an experimentally generated tongue cancer model, application of 600 mg/kg/day of PDTC led to a significant reduction in the size of the tumor. This was supported by the biochemical parameters.