The cause of coronavirus disease 2019（COVID-19） is toxin of pestilence. The pathogenesis is characterized by cold and heat in complexity

prosperous pathogen with asthenia vital qi

toxin and pathogen covering the whole process. The lesion is in lung and may invade heart

kidneys and other organs in the course of time. It should be treated from "cold" and "dampness". Three cases of COVID-19 treated by the method of expelling pathogen and resolving toxin were given as examples. The combination of cold and heat drugs

tonification and purgation drugs were emphasized. Resolving toxins

clearing heat to release the exterior

draining dampness

and benefiting qi were combined

resulting in dissipating pathogen and recovery of healthy qi. It can significantly shorten the time of fever

improve the clinical symptoms and lung inflammation of patients

and can facilitate the corona virus nucleic acid turning to negative.