Acute respiratory syndrome, associated with coronavirus 2 (SARS-CoV-2), is the most important medical and epidemic problem of today. The biggest challenge is to find an effective treatment and to reduce the need for hospitalisation. In the article, the patients with mild to moderate coronavirus disease 2019 (COVID-19) treated with doxycycline with significant improvement have been discussed. Doxycycline is a known antibiotic, but also an anti-inflammatory and immunomodulatory drug, so it seems to be ideal for the treatment of COVID-19. Doxycycline, as an easily available and low-cost medication, should be considered as a COVID-19 therapy in all patients in the first days of the symptoms of a SARS-CoV-2 infection. Due to its immunomodulatory, anti-inflammatory, cardioprotective and antiviral effects, it seems to be an ideal drug for patients with mild, moderate and severe disease. A large multicentre study is needed to evaluate the effects of this medication.