Upper respiratory tract infections (URTI) are a large group of infectious diseases (mainly viral and bacterial), affecting the mucous of the nasal cavity, paranasal sinuses, pharynx and larynx. URTI are very common in inpatient and outpatient clinical practice. In this article, we present a clinical case of Patient N., 20 years old, consulted with upper respiratory tract damage caused by Chlamydia pneumoniae. The patient admitted to clinical diagnostic center on 07.07.2021 with complaints of pain in the left maxillary sinus with irradiation to the left temporal region, difficulty in nasal breathing, pain in the pharynx, aggravated by swallowing, and increased body temperature (37,5 °C). The patient was consulted by an interdisciplinary team (ENT doctor and clinical pharmacologist). After carrying out physical, instrumental and laboratory tests the diagnose Chlamydia pneumoniae - associated URTI was established and, the patient was prescribed doxycycline at a dose of 100 mg 2 two times a day on the 1st day following by 100 once a day for the next 6 days with a positive effect. The doxycycline was choisen because of a more favorable safety and efficacy profile compared to fluoroquinolones and some other antibacterial agents. After 7 days of treatment, the patient recovered completely. Among all doxycycline drugs available on the market of the Russian Federation, Doxycycline Express (JSC Pharmstandard-Leksredstva) stands out due to its high quality, bioequivalence to the original drug and comfortable regime of use due to the dosage form (dispersible tablets), that increases the patient’s compliance and allows it to be used by some special categories of patients (elderly and senile patients, patients with dysphagia, etc.