Study aim: Determining the effect of oxygen therapy on patients referred to Kashani hospital emergency department for headache for 15 to 60 minutes by visual analog scale (VAS). Design: Patients will be divided into two intervention and control groups based on a random number table, sample size 60 (30 people in each group), double-blind. Settings and conduct: This study will be performed in the emergency department of Kashani hospital in Shahrekord. Participants/Inclusion and exclusion criteria: Age between 18 to 50 years, no mental illness, no brain pathology (brain CT obtained from all patients) or neurological defects in the examination, no high blood pressure, no cancer, no pregnancy or lactation, willingness to cooperate, absence of lung diseases such as asthma, pneumonia, absence of any previous disease being treated. Intervention groups: Control group: in addition to routine treatment, a mask attached to the air container will be located for the patient. Intervention group, in addition to the painkiller, oxygen therapy will be started with a non-rebreather mask. The amount of oxygen consumed will be at least 15 liters. The amount of pain will be measured and recorded using VAS 0, 15, 30, 45, and 60 minutes after the start of treatment by the patient. Main outcome variables: Headache