Therefore, the aim of the present study was twofold: (i) to compare the effects of photodynamic therapy and topical corticosteroid therapy on the activity of selected salivary antioxidants (SOD, CAT, Px, GSH) in patients with OLP in a randomized clinical trial setting, and (ii) to assess the correlations between salivary antioxidant activity and changes in lesion size and pain intensity (VAS) according to the applied treatment modality. The gene discussed is CAT; the disease is oral lichen planus.