Selaginella uncinata polysaccharide SUSP-4 significantly improves the histological appearance of the colon in Inflammatory Bowel Disease (IBD) models, upregulates the expression of key intestinal barrier proteins (Occludin and ZO-1), and suppresses macrophage activation (downregulating the expression levels of CD68 and CD86). This evidence concerns the gene CD86 and inflammatory bowel disease.