Study aim: Determining the effect of aromatherapy with lavender on the level of satisfaction, pain and physiological indicators of patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) admitted to the selected hospitals of Shahid Beheshti University of Medical Sciences. Design: A parallel randomized clinical trial with control and intervention groups, a blind strain on 80 patients. For randomization, the random number function table of Excel software will be used. Settings and conduct: The place of intervention is the gastroenterology department of the hospital. In order to reduce the communication between the two experimental and control groups, the intervention will be carried out in separate rooms. The method of performing aromatherapy will be that four drops of lavender essential oil with a concentration of 2% will be dripped on sterile gauze and placed on the chest of patients in the intervention group, and they will be asked to breathe for at least 30 minutes before Perform the procedure and inhale it. In the control group, normal saline is used. Participants/Inclusion and exclusion criteria: Entry conditions: not having a history of drug sensitivity, having the necessary cooperation to perform the procedure, not receiving painkillers before and after the procedure in the control and intervention groups, the same anesthesia protocol. Not having a smell problem Do not enter: any allergy to lavender Intervention groups: The method of performing aromatherapy will be that four drops of lavender essential oil with a concentration of 2% will be dripped on sterile gauze and placed on the chest of patients in the intervention group, and they will be asked to breathe for at least 30 minutes before Perform the procedure and inhale it. In the control group, normal saline is used. Main outcome variables: satisfaction; the pain; Physiological indicators