A common sterol in Chinese herbal medicine, β sitosterol, prevents the shortening of the colon in C57BL/6 mice with colitis induced by TNBS, decreases the general score and myeloperoxidase activity, downregulates the proinflammatory cytokines TNF-α, IL-1β, and IL-6, and the inflammatory enzyme cyclooxygenase (COX)-2, and inhibits the activation of NF-κB60. The gene discussed is IL1B; the disease is colitis.