The purpose of this study was to study the immunomodulatory and clinical properties of the drug in patients with RAS. In order to assess the effect of the LAZOLEX on the clinical course of RAS, 2 groups of patients were formed (In total 50 patients): 1) The first group (control), which included 20 patients, who received a traditional treatment (application of A and E vitamins, cedar oil, Solcoseryl dental adhesive paste); 2) The second group (main), which included 30 patients, who were treated with LAZOLEX. (5% gel was applied to the damaged areas of the lips and oral mucosa, daily for 10 days). Examination of patients with RAS revealed noticeable changes in the immune system, affecting all its factors, which largely depended on the severity of the process, i.e., the most severe immunosuppression was recorded in patients with severe stomatitis. Therefore, the obtained fact was a sufficient justification for the use of immunomodulatory agents as adjuvant therapy, in a particular case - LAZOLEX. We note that this drug significantly increases the effectiveness of traditional treatment, and from an immunological point of view, we can reasonably assert that it contributes to the immunorehabilitation of patients. Conducted clinical, laboratory and immunological studies allow us to recommend LAZOLEX for active use in dental practice for RAS.