Coronavirus disease 2019 (COVID-19) has resulted in more than 8.7 million laboratory-confirmed cases and 0.46 million deaths globally (1). Few therapies, if any, have been shown to rapidly ameliorate the respiratory symptoms and prevent against the disease progression. An important mechanism contributing to dyspnea and disease progression in patients with COVID-19 might be the increased work of breathing because of the heightened airway resistance (2). Inhalation of hydrogen/oxygen mixed gas (H2-O2) might have a role in the treatment of COVID-19 given the decreased resistance compared with room air when passing through the airways.
