Oral administration of the EVs derived from tea leaves can reduce the production of ROS, inhibit the expression of proinflammatory cytokines (TNF-α, IL-6, IL-12), increase the anti-inflammatory activity of macrophages (IL-10), inhibit the inflammatory intestinal response, restore the damaged colon barrier, enhance the diversity and overall abundance of intestinal microbiota, and thus prevent or alleviate IBD and colitis related colon cancer. The gene discussed is TNF; the disease is colitis.