Keywordschlorine dioxide (ClO 2 ), nasal irrigation, COVID-19, SARS-CoV-2, respiratory infectious diseases Chlorine dioxide (ClO 2 ) is a high-level disinfectant that is safe and widely used for sterilization. Due to the limitations on preparing a stable solution, direct use of ClO 2 in the human body is limited. Nasal irrigation is an alternative therapy used to treat respiratory infectious diseases. This study briefly summarizes the available evidence regarding the safety/efficacy of directly using ClO 2 on the human body as well as the approach of nasal irrigation to treat COVID-19. Based on the available information, as well as a preliminary experiment that comprehensively evaluated the efficacy and safety of ClO 2 , 25-50 ppm was deemed to be an appropriate concentration of ClO 2 for nasal irrigation to treat COVID-19. This finding requires further verification. Nasal irrigation with ClO 2 can be considered as a potential alternative therapy to treat respiratory infectious diseases, and COVID-19 in particular.