X-rays and gamma radiation delivered to the abdominal region for cancer treatment encompasses severe damage to the intestinal mucosa, which significantly impairs a patient's quality of life. To a great extent the deleterious effects of x-radiation originate from radiolysis-induced reactive oxygen species. The well-researched powerful antioxidant Pycnogenol was administered orally to rats prior to x-irradiation with 15 Gy. Histological sections of the intestines showed a dramatically better condition of the mucosal layers compared with the irradiated control animals administered water without Pycnogenol. Pycnogenol treatment significantly preserved the height and number of villi as well as the glandular layer and a diminished number of congested vases were present. No intestinal alterations were seen in control animals receiving Pycnogenol in the absence of radiation. It is concluded that Pycnogenol provides significant protection from ionizing radiation damage.