Study aim: Determining the effect of Benson sedation on the severity of headache caused by intravenous nitroglycerin infusion. Design: The present study is a parallel-group randomized controlled clinical trial. Eligible patients are divided into two groups of 30: intervention and control. Settings and conduct: For the intervention group, the relaxation method will be performed. Participants/Inclusion and exclusion criteria: Inclusion criteria: A new diagnosis of ACS, Age above 18 years, No migraine headaches and any other headaches, No drug addiction, Absence of neurological disorders under drug treatment, Absence of headache before starting nitroglycerin injection, Absence of pain in other parts of the body (except chest pain),Absence of speech and vision disorders, Not using oral and topical nitrate drugs Exclusion criteria: Non-cooperation due to increased chest pain and worsening of the patient's hemodynamic symptoms, need to increase the dose of nitroglycerin (more than 5 micrograms per minute), and non-cooperation with the researcher. Intervention groups: For the intervention group, the relaxation method will be performed. This intervention will be performed after 5 minutes of teaching the patient how to do deep breathing for 15 minutes in the presence and with the help of a nurse. Intravenous nitroglycerin infusion will be performed at a dose of 5 micrograms per minute and a rate of 6 drops per minute. Main outcome variables: Benson's Relaxation Headache