The article presents data concerning effectiveness of the immune agent alpha/betadefensins as a accompanying chemotherapy/radiotherapy drug at the 1st stage oftreatment of 73 patients with cancer of the oral cavity and oropharynx.The purpose of the work – to evaluate the effectiveness of the immune agent alpha/betadefensins as a drug, accompanying radiation or chemoradiation therapy, at the 1st stageof treatment of patients with the oral cavity and oropharynx cancer.Materials and methods. Patients of the I and II groups under study received radiation andchemoradiation therapy, respectively, as well as the immune agent alpha/beta defensins2.0 ml 2 times a day intramuscularly 2 days before the start of the special treatment for5 days, as well as during the next 10 days of treatment 1 time per day. Patients of III-IVgroups, comparative, received similar treatment, but without immunotherapy.The results. According to the time of the appearance of epitheliitis and changes in itsdegree in the dynamics of treatment, the best results were obtained in patients of groupI, since the first inflammation manifestations in the oral cavity or oropharynx developedat the latest – at a dose of 22 Gy, while in patients of group III they appeared at a dose of12 Gy (p<0.05) and in larger quantity of patients (12%). The transition of the first degreeof epitheliitis to II and III in the first group took place in a smaller number of patients,that indicates a positive effect of the immunopreparation on the severity of epitheliitis.The number of cases of epitheliitis of the III degree is indicative: 4% of patients of theI group against 79% of patients of the III group and 60% of patients of the IV on averageafter 30 Gy (p<0.05). Only in the IV group there were patients who developed ulcerativeepitheliitis (IV degree). The number of patients with radiodermatitis of the I degree in theI group was 30% less compared to the III group, in the II group – 29% less than in groupIV. Radiodermatitis of the II degree was observed in a small number of patients – 5% inthe II group and 11% in the III group Xerostomia occurred in 90% of patients regardlessof the method of treatment and the use of immunotherapy as accompanying drug ofspecial treatment. Paraheusia and ageusia are more pronounced in groups III and IV.Conclusions. The phenomena of radiation epitheliitis develop later in the treatmentperiod and in a smaller number of patients, who received alpha/beta defensinimmunotherapy compared to patients, who did not receive immunotherapy. A positiveeffect of immunotherapy can also be considered a decrease in the number of patients withIII-IV degrees of epitheliitis.