The aim of this study is to evaluate the effect of diclofenac suppository on dosage of narcotics during colonoscopy, in order to make sufficient tolerance to run a successful safety procedure and to obtain immediate consequence. This study will be done using 524 patients, after taking Informed consent, who candidate out-patient or in-patient colonoscopy for any reason. Patients with colonoscopy-phobia, history of previous intestinal surgery or inflammatory bowel disease or cardiopulmonary comorbidities or in conditions of contraindication of NSAIDs’ usage (e.g. hypersensitivity), will be excluded. This study is a prospective, randomized, single-blind, placebo controlled. Besides the same dug regiments of midazolam and fentanyl for both groups before colonoscopy, Diclofenac suppository was administered to case group 30 minute before procedure. According to each group, Duration of colonoscopy & Narcotic dosage which are used during colonoscopy, will be documented. At the end of colonoscopy, patients pain will be scored by nurse, using visual analogue scale.