• Signing and dating of the IPP informed consent form by the patient.

• Women and men between the ages of 18 and 65 years, inclusive, at the time of signing the informed consent form.

• Clinical diagnosis of acute respiratory viral infection of the upper respiratory tract (ICD-10 code J00-J06) or acute bronchitis (J20, J21 according to ICD-10).

• Onset of disease symptoms no more than 3 days prior to screening.

• Presence of a patient with a dry unproductive cough.

• Frequency of cough episodes ≥10 in the past 24 h before the screening visit and randomization.

• Cough frequency rated by the patient as 3-4 on the daytime cough section and 2-4 on the nighttime cough section of the Daytime and Nighttime Cough Scales.

• Patient rating of cough severity on the DRS ≥ 4 points.

• No indication for therapy due to BHSA infection at the time of study inclusion: negative rapid test for Group A β-haemolytic streptococcus.

⁃ For women of preserved reproductive potential, a negative pregnancy test and agreement to use approved contraceptive methods for the duration of study participation, beginning at visit 0, and for 3 weeks after the end of the study; for men, agreement to use approved contraceptive methods throughout the study participation period and for 3 weeks after the end of the study.