Mouse experiments demonstrated that the gut microbiota activates the lung TLR4/NF-κB signaling pathway via the lung intestinal axis, aggravating LPS-induced acute lung injury (ALI) and that fecal microbiota transplantation can restore intestinal microbiotal homeostasis, increase intestinal flora diversity, and inhibit LPS-induced ALI (Tang et al., 2021). This evidence concerns the gene TLR4 and acute respiratory distress syndrome.