It is relevant to highlight that bromhexine has been initially identified as a potent inhibitor (IC50 = 0.75 μM) of the transmembrane serine protease 2 (TMPRSS2) of SARS-CoV (Shen et al., 2017), being involved also in the binding and infection (mainly via a nonendocytotic route) of SARS-CoV-2 to host cells (Gil et al., 2020). This evidence concerns the gene TMPRSS2 and infection.