Objective: Since the higher quality of pain control with less complication is always an important issue in emergency departments, this study aims to compare the effects and complications of narcotic and narcotic in addition to naloxone. Design: A double-blind randomized clinical trial in which randomization will be performed using the random number table. Inclusion criteria: Renal colic and pain score of 7-10 based on VAS. The exclusion criteria are pregnancy, sensitivity to the drugs used in the study, morphine contraindications, history of drug dependence, receiving a calmative drug during 6 hours before the visit, peritoneal symptoms in abdominal examination, history of cardiovascular diseases, psychosis and patient withdrawal to participate in the study, acute ischemic disease, age above 60, absence of renal colic in further studies. Sample size: 280 subjects. Intervention: A group of patients with renal colic will receive morphine (0.1 mg / kg) and placebo through a double-blind random method and the other group will receive the same dose of morphine with naloxone (0.001 mg/kg). An additional dose of 0.05 mg/kg morphine will be given to both groups after twenty minutes if needed (no pain control). Duration of intervention: From the beginning of admission to the emergency department. Primary outcomes: Pain, nausea, sedation, number of breaths, and blood pressure.