In a retrospective cohort study, 33 patients with confirmed COVID-19 infection between 1/17/2020 and 2/13/2020 were divided into two groups: one group received combination therapy of arbidol and lopinavir/ ritonavir (LPV/r) and the other group received LPV/r only. Oral drug administration lasted for 5-21 days. Drug dosages were as follows: 200 mg of arbidol every 8 hours, 400 mg of lopinavir every 12 hours, and 100 mg of ritonavir every 12 hours. Participants had pneumonia but were not receiving invasive ventilation. Nasopharyngeal and stool specimen tests for COVID-19 and chest CT scans were performed regularly. The outcomes of the study showed that after 7 days, 75% and 69% of patients in the combination therapy group and 35% and 29% of patients in the monotherapy group had negative nasopharyngeal specimen test results and improving CT scans, respectively. Although there was no significant difference between the positive stool tests for COVID-19 of the two groups, it is suggested that the combination therapy drugs can be excreted in feces at high concentrations, making this combination potentially useful for patients with stool-positive results for the virus. Combination therapy was well tolerated by participants.