Aim: To determine the incidence of acute colitis following colonoscopic procedure in our endoscopy unit and prove the likely connection of this diagnosis with exposition to glutaraldehyde. Methods: We analyzed the medical records of the colonoscopic examinations that were performed in our endoscopy unit from 2001 through 2006 and selected the cases of outbreak of acute colitis shortly after a colonoscopy. Then we determined its incidence in each year and compared the incidences between the years when 2% glutaraldehyde solution had been used for colonoscope disinfection and the years 2004–2006, when glutaraldehyde solution was replaced by Electrolyzed Acid Water (EAW) system. Results: There were 4 537 patients examined through 2001–2003 when glutaraldehyde was being used for endoscope disinfection, from which 27 experienced glutaraldehyde- induced colitis (9, 8 and 10 respectively), the overall incidence being 5,95 cases per 1000 patients (6,5, 5,05 a 6,36 respectively). The average time between the colonoscopy and the onset of symptoms was 2,3 days, the mean period being 2 days. Women were affected more often (70,6 % vs. 29,4 %). In the period when EAW system was being used (2004–2006), no single case of acute colitis following a colonoscopy was found. Conclusion: We can thus conclude that our patients experienced glutaraldehyde-induced colitis.

        Key words: Colonoscopy, glutaraldehyde, colitis, EAW system.