Creatine belongs to a buffering system of cellular ATP level and shows direct antioxidant activity. Our aim was to investigate if creatine could improve enterocytes antioxidant response and limit the oxidative injury induced by anoxia and reoxygenation. Rat jejunal and ileal tracts were everted and incubated in vitro under normoxic, anoxic and reoxygenation conditions, in the absence or presence of creatine. (Na+, K+)-ATPase, g-GT and antioxidant enzymes activities were determined in mucosal homogenate, as well as malondialdehyde production and HSP70 expression. In both tracts creatine increases (Na+, K+)-ATPase activity, while antioxidant activities and malondialdehyde level are unaffected. g-GT activity increases only in ileum and HSP70 expression only in jejunum. Anoxia stimulates antioxidant activities to a greater extent in jejunum compared to ileum; reoxygenation has no further effects, but enhances malondialdehyde production in both tracts. The protective action of creatine, in reoxygenation, is greater in jejunum as for its stimulation of antioxidant activities; however, in jejunum a prooxidant action of creatine is suggested since malondialdehyde production is enhanced by its presence; on the contrary in ileum, where HSP70 is overexpressed in reoxygenation, peroxidation level is significantly reduced. Then, creatine seems to potentiate the defensive response of both tissues, in jejunum by means of cell antioxidant equipment, in ileum by the involvement of HSP70.