In mice with OVA-induced asthma, EGCG treatment significantly reduced asthma symptoms and decreased numbers of eosinophils and neutrophils in the BALF, decreased IL-2, IL-6, and TNFα, increased IL-10 concentrations, diminished percentage of Th17 cells, increased percentage of Treg cells, and decreased expressions of TGF-β1 and phosphorylated (p)-Smad2/3 [37]. Here, SMAD2 is linked to asthma.