Recent studies using chronic unpredictable mild stress (CUMS)-induced and endotoxin-induced depression mice have demonstrated that baicalin can improve depressive-like behavior and neuroinflammation by inhibiting the harmful overexpression of Toll-like receptor 4 (TLR4) by inhibiting the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT)/forkhead Box O1 (FOXO1) pathway (Guo et al., 2019). This evidence concerns the gene TLR4 and depressive disorder.