Objectives: To develop a new Chinese medicine (CM)-based drug and to evaluate its safety and effect for suppressing acute respiratory distress syndrome (ARDS) in COVID-19 patients.Methods: A putative ARDS-suppressing drug Keguan-1 was first developed and then evaluated by a randomized,controlled two-arm trial.The two arms of the trial consist of a control therapy (alpha interferon inhalation,50 μ g twice daily;and Iopinavir/ritonavir,400 and 100 mg twice daily,respectively) and a testing therapy (control therapy plus Keguan-1 19.4 g twice daily) by random number table at 1:1 ratio with 24 cases each group.After 2-week treatment,adverse events,time to fever resolution,ARDS development,and lung injury on newly diagnosed COVID-19 patients were assessed.Results: An analysis of the data from the first 30 participants showed that the control arm and the testing arm did not exhibit any significant differences in terms of adverse events.Based on this result,the study was expanded to include a total of 48 participants (24 cases each arm).The results show that compared with the control arm,the testing arm exhibited a significant improvement in time to fever resolution (P=0.035),and a significant reduction in the development of ARDS (P=0.048).Conclusions: Keguan-1-based integrative therapy was safe and superior to the standard therapy in suppressing the development of ARDS in COVID-19 patients.