AIM: Evaluation of efficacy, safety, tolerability, and determination of the optimal dose of riamilovir in patients diagnosed with acute respiratory viral infection (ARVI). MATERIALS AND METHODS: The study included 270 patients with uncomplicated ARVI of mild and moderate severity (with a laboratory-confirmed PCR method for the presence of ARVI antigens, absence of influenza virus antigens). Patients were included in the study after signing an informed consent. Patients were randomized into 3 groups in a 1:1:1 ratio of 90 patients in each group. Completed the study in accordance with the Protocol: 267 patients. The study involved patients diagnosed with ARVI. RESULTS: Confirmed the efficacy, safety and tolerability of the drug riamilovir. Adverse drug reactions associated, in the opinion of the doctor, with taking the drug and resulting in discontinuation of the drug, were not noted in this study. CONCLUSION: As a result of clinical study, the effectiveness of both ARVI treatment regimens with drug riamilovir has been shown. There were no differences in the effectiveness and safety of the proposed treatment regimens. Practical use of both treatment regimens is recommended. However, according to the authors, taking the drug 3 times a day is much more convenient for patients, improves the quality of life and adherence to therapy.