Materials and methods: Forty-eight Sprague-Dawley rats were divided into control (C, n = 6), irradiation (IR, n = 14), fluoropyrimidine (5-FU, n = 14)-treated, IR + 5-FU (n = 14)-treated groups. Half of each irradiated and/or 5-FU-treated groups were previously fed with IED containing arginine, omega-3-fatty acids and RNA fragments, while the other half were fed a standard rat diet (SD) for eight days before the induction of IR or injection of 5-FU. In IR groups, whole abdominal irradiation (11 Gy) was performed with 6 MV photons. In the 5-FU groups, fluoropyrimidine (100 mg/kg) was administered intraperitoneally 30 min prior to irradiation. All animals were sacrificed on the 4th day of IR or 5-FU injection.