A headache when you smoke may be caused by vasodilation, excitement or elevated blood pressure. The main ingredient in cigarette is nicotine, which has obvious vasodilator effect, most patients do not have symptoms when the blood vessels are dilated, but it may cause headache, nausea and vomiting if it is seriously dilated. If the patient is over-excited, it is easy to cause an increase in 5-hydroxytryptamine secretion in the body, 5-hydroxytryptamine secretion increases easily caused by vasodilatation, which may lead to headaches. When over-excited, it is easy to cause an increase in blood pressure, and when blood pressure rises, the patient may also have a headache, and the patient’s blood pressure should be monitored. If smoking may cause vasospasm, vasospasm easily caused by the brain blood supply obstacles, serious cases may cause limited brain tissue ischemia, hypoxia, patients can also appear headache. Tobacco contains other toxic substances, it may be that some toxic substances are allergic to the human body, which may cause headaches in patients. Patients in general should smoke less and try to quit smoking.