The authors submit the case-history of a 42-year-old man with chronic renal insufficiency caused by chronic glomerulonephritis. This patient was indicated on account of bulbitis with confirmed Helicobacter pylori infection for one-week eradication treatment by a combination of omeprazole (20 mg twice a day), amoxycillin (500 mg twice a day) and claritromycin (250 mg twice day). The first manifestations of colitis developed already on the second day after the onset of treatment. The disease first took the course of trivial colitis without temperatures, only with diarrhoea which receded after treatment with Hylak forte. The patient completed the whole one-week eradication treatment. A further exacerbation of colitis occurred after administration of a laxati- ve which he took because of constipation which followed after the period with diarrhoea. At the time the patient was already for ten days without antibiotics. The second attack of colitis was much more serious with septic temperatures and signs with incipient disseminated intravascular coagulopathy. Colonoscopic and histological examination revealed pseudomembranous colitis. In the faeces toxin of Cl. difficile was detected by the ELISA method. The condition was complicated by the development of respiratory insufficiency requiring artificial ventilation. The life threate- ning condition was finally successfully controlled by intensive therapy but the total period of hospitalization exceeded 40 days and the patient's complaints persisted for more than two months.

        Key words: pseudomembranous colitis – Helicobacter infection – eradication treatment