5-Fluorouracil (5-FU)-induced intestinal mucositis is one of the most common morbidities in chemotherapy and involves the reactive oxygen species (ROS) system, apoptosis, and inflammatory cytokines. Rebamipide exerts a mucosal-protective effect, mediated through several mechanisms. The aim of this study was to evaluate the effects of rebamipide in 5-FU-induced mouse small-intestinal mucositis. BALB/c mice were assigned randomly to four groups; (1) control group ( n =10; receiving saline orally for 6 d), (2) rebamipide group ( n =10; 150 mg/kg rebamipide for 6 d orally), (3) 5-FU group ( n =10; 30 mg/kg 5-FU for 5 d, intraperitoneally (i.p.)), and (4) rebamipide +5-FU group ( n =10; 150 mg/kg rebamipide for 6 d orally and 30 mg/kg 5-FU for 5 d, i.p.). Body weights and diarrhea scales were assessed. At day 5, the mice were sacrificed. Small intestinal tissue was used for: (1) hematoxylin and eosin (HE) staining for determination of small intestinal villi height, (2) terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) assay, (3) immunohistochemistry for inducible nitric oxide synthase (iNOS), F4/80, and transforming growth factor (TGF)-β1, (4) measurement of serum and tissue GSH levels, and (5) measurement of serum tumor necrosis factor (TNF)-α levels. Rebamipide attenuated the severity of mucosal injury reflected by body weight changes, degrees of diarrhea, and heights of villi. Rebamipide reduced the expression of iNOS and TGF-β1, apoptosis, macrophage accumulation, serum TNF-α levels, and prevented reductions in serum and tissue glutathione (GSH) levels by 5-FU administration. These results suggest that rebamipide promotes several mechanisms of mucosal protection and attenuated the 5-FU-induced mucosal injury. In conclusion, administration of rebamipide may have significant protective effects against 5-FU-induced intestinal mucositis.