Bufei huoxue capsules (BFHX), manufactured products of traditional Chinese medicine, have demonstrated anti-inflammatory properties and efficacy against chronic pulmonary diseases and COVID-19. This study was designed to further determine the clinical efficacy of BFHX in diverse patient subgroups during the convalescent phase of COVID-19, extending upon previously reported findings from a multicenter randomized controlled trial. Patients who had clinically recovered from COVID-19 were blindly assigned to BFHX or placebo groups. All enrolled patients underwent chest computed tomography (CT) imaging, 6-min walking distance (6MWD) test, and fatigue assessment inventory (FAI) at monthly follow-up for 3 months. A post hoc subgroup reanalysis was performed on subgroups of sex, age, severity of acute illness, and positive/negative IgG antibody against S antigen variants. A total of 129 patients were enrolled in BFHX (