Aims: The aim of this double-blind randomized clinical trial was to determine the effects of FBX in comparison with hydroxychloroquine (HCQ) on clinical symptoms, laboratory tests and chest CT findings in patients with COVID-19-causing moderate symptomatic disease. Methods: We conducted a randomized, double blind clinical trial involving adult outpatients’ patients with COVID-19 infection, which causes the moderate respiratory illness. Sixty patients were randomly assigned to receive either FBX or HCQ for 5 days. The measured variables were clinical and laboratory data including rate of fever, cough, berating rate, C-Reactive Protein level, lymphocytes count at onset of admission and was well as at 5 days of treatments. In addition, CT lesions were evaluated on admission and 14 days of treatments in both groups. Results: Fever, cough and tachypnea significantly mitigated in both groups after five days of treatments. The lymphocytes count significantly increased in both treatment groups and the CRP values were dropped in normal range (negative) in major of patients receiving FBX or HCQ treatment. It was not observed any significantly difference between FBX and HCQ in frequency of these symptoms. The mean percentages of CT abnormality scores were significantly reduced to 7.3% and 8% after 14 days of FBX and HCQ treatments, respectively. In adult outpatients with moderate symptomatic Covid-19, the effectiveness of FBX was same to HCQ in improvement of clinical manifestations, laboratory tests and CT lesions. Conclusion: These findings suggest FBX as an alternative treatment for Covid-19 infection in patients with contraindication or precaution to HCQ.