To explore the effect of C3G on intestinal mucosal injury in 5-FU induced BALB/c mice. Mice were randomly divided into normal, model and C3G groups. After the last administration, mice were anesthetized, and calculated the thymus and spleen indexes. The ileum was used to stain with H&E observation. Serum levels of IL-1β, IL-6, IL-10 and TNF-α were determined by ELISA kits. Compared with the normal group, the model group had diarrhea, body weight and thymus and spleen index decreased significantly, intestinal villus epithelial cells fell off, crypt structure was destroyed, and inflammatory cell infiltration was observed. The body weight, thymus and spleen indexes of the treatment group and the prevention group decreased less, and the levels of TNF-α, IL-1β and IL-6 were significantly decreased, and the level of IL-10 was significantly increased relative to the model group. The intestinal villi structure was relatively complete, and a small amount of crypt structure was destroyed, with a small amount of inflammatory cell infiltration, which reduced the mucosal damage. The administration of C3G could protect intestinal mucosa from 5-FU-induced injury.