Outbreak of coronavirus disease 2019 occurred in Wuhan and has rapidly spread to almost all parts of world GB-1, the herbal formula from Tian Shang Sheng Mu of Chiayi Puzi Peitian Temple, is used for the prophylaxis of SARS-CoV-2 in Taiwan In this study, we investigated that the effect of GB-1 and the index compounds of GB-1 on the ACE2 and TMPRSS2 expression through in vitro and in vivo study In our result, GB-1 can inhibit ACE2 and TMPRSS2 protein expression in HepG2 cells , 293T cells, and Caco-2 cells without cytotoxicity For the mouse model, GB-1 treatment could decrease ACE2 and TMPRSS2 expression levels of the lung and kidney tissue without adverse effects, including nephrotoxicity and hepatotoxicity In the compositions of GB-1 , 0 5-1 mg/ml of Glycyrrhiza uralensis Fisch ex DC extract could not inhibit ACE2 mRNA and protein expression in HepG2 cells In addition, theaflavin-3-gallate could inhibit protein expression of ACE2 and TMPRSS2 without significant cytotoxicity Our results suggest that GB-1 and theaflavin-3-gallate could act as potential candidates for prophylaxis or treatment of SARS-CoV-2 infection through inhibiting protein expression of ACE2 and TMPRSS2 for the further study