Coronavirus disease 2019 (Covid-19) has resulted in a global outbreak. Few existing targeted medications are available. Lianhuaqingwen (LH) capsule, a repurposed marketed Chinese herb product, has been proven effective for influenza. To determine the safety and efficacy of LH capsule in patients with Covid-19. We did a prospective multicenter open-label randomized controlled trial on LH capsule in confirmed cases with Covid-19. Patients were randomized to receive usual treatment alone or in combination with LH capsules (4 capsules, thrice daily) for 14 days. The primary endpoint was the rate of symptom (fever, fatigue, coughing) recovery. We included 284 patients (142 each in treatment and control group) in the full-analysis set. The recovery rate was significantly higher in treatment group as compared with control group (91.5% vs. 82.4%, p = 0.022). The median time to symptom recovery was markedly shorter in treatment group (median: 7 vs. 10 days, p < 0.001). Time to recovery of fever (2 vs. 3 days), fatigue (3 vs. 6 days) and coughing (7 vs. 10 days) was also significantly shorter in treatment group (all p < 0.001). The rate of improvement in chest computed tomographic manifestations (83.8% vs. 64.1%, p < 0.001) and clinical cure (78.9% vs. 66.2%, p = 0.017) was also higher in treatment group. However, both groups did not differ in the rate of conversion to severe cases or viral assay findings (both p > 0.05). No serious adverse events were reported. In light of the safety and effectiveness profiles, LH capsules could be considered to ameliorate clinical symptoms of Covid-19. Copyright © 2020 Elsevier GmbH. All rights reserved.