Andrographolide can restrain the activation of the IL-23/IL-17 axis and the production of downstream proinflammatory cytokines, thereby inhibiting the inflammatory response; reducing the levels of serum proinflammatory factors, such as TNF-α, IL-1β, IL-6, and IL-23; and inhibiting the Th17-cell immune response in patients with ulcerative colitis (Zhu et al., 2018a). Here, IL17A is linked to ulcerative colitis.