The course of a disease with recurrent massive bleeding into gastrointestinal tract of unknown ethiology is described in 68 years old female patient. As far as neither long-term intensive antisecretory treatment was shown to be protective against development of complications, the suspicion for Zollinger Ellison syndrome (ZES) was raised. The patient was admitted to Medical Clinic II with severe posthemorrhagic anaemia, whereas blood transfusions were required. When endoscopised, extremely fragile mucosa with numerous erosions and ulcerations covered by fibrin and mucus were found. The diagnoses such as Crohn disease, amyloidosis, mycosis or parasitosis were excluded. The same holds true for ZES. After re-evaluation of the patient’ records and after the consultations with pathology and radiotherapy experts, the case was concluded as the postirradiation segmentary duodenitis after adjuvant radiotherapy for primary diagnosis of Grawitz tumor after nefrectomy of the right kidney. Antisecretory therapy was replaced by mucoprotective and vasoprotective therapy. The patient feels well on the administered therapy, while blood count and weight are stabile. There has been no need for blood transfusion for six months. Both histological and endoscopis findings were restored to normal in the affected part of the duodenum.

        Key words: radiation, duodenitis, bleeding, treatment