Background and study aims: Anxiety before colonoscopy may have adverse consequences and increase requirements for sedation and analgesics. We aimed to examine the effects of adding an information video to our usual preprocedural information. Patients and methods: 162 colonoscopy patients were randomly assigned to video (72) or no video (90) groups. Patients in the video group watched a video on colonoscopy procedures and cleansing. The patients' situational anxiety was measured using the State-Trait Anxiety Inventory (STAI) questionnaire. Patients rated pain and overall satisfaction related to the procedure. The colonoscopist and the endoscopy nurse, who were blinded to the patient's allocation, completed questionnaires on use of medication, procedure outcome, and their assessments of patient pain and toleration of the procedure. Results: There were no differences between the two groups concerning situational anxiety (mean STAI-State score 45.0 ± 13.3 vs. 45.9 ± 12.9, P= 0.7), rating of pain, tolerability of the procedure, or the willingness to undergo a future colonoscopy. The staff rated the outcomes equally in the two groups. There was no difference in use of midazolam, but patients, who had seen the video used higher doses of fentanyl (P < 0.02). Situational anxiety ratings were significantly higher in women, and they found the procedure significantly more painful (P= 0.001) and were less satisfied (P < 0.05). Conclusions: An information video shown to patients preparing for colonoscopy had no impact on tolerability or anxiety. Colonoscopy is less tolerable and more painful for women and this is probably related to a higher degree of anxiety. Endoscopy personnel should be aware of these gender differences and adjust information and medication accordingly.