Abstract: [Abstract] Objective The objective of our study was to explore the impact of selenium on immune statuses of patients with oral lichen planus. Methods The method was to treat the 30 patients with oral lichen planus using selenium, and to observe the changes of T lymphocyte subsets and clinical symptoms of OLP before and after the treatment. Results We found that before the treatment, the ratios of CD3+，CD4+ and CD4+/CD8+ of patients (p 0.05) were obviously lower than those of healthy people(P<0.05). After the treatment with selenium, the ratios of CD3+、CD4+ and CD4+/CD8+ of patients significantly increased(P>0.05), and the ratio of CD4+/CD8+ got back to normal. The clinical symptom ceased and local lesion almost healed. Conclusion We conclude that selenium is effective in the treatment of patients with oral lichen planus, through regulating the ratios of CD3+、CD4+ and CD4+/CD8+.