A network pharmacology study showed that 140 active ingredients in XiaoChaiHu Decoction was for pneumonia treatment and immune regulation through 95 key targets such as IL-6, inducible nitric oxid synthase (NOS2), and estrogen receptor 1 (ESR1), involving TNF and IL-17 signaling pathways, and influenza A, of which 12 ingredients had direct anti-SARS-CoV-2 activity including baicalein, formononetin, quercetin [67]. This evidence concerns the gene NOS2 and susceptibility to pneumonia measurement.