Smoking and second-hand smoke from cigarettes, cigars, and pipes can contribute to headaches for both the smoker and the non-smoker. Nicotine, one of the components of tobacco, stimulates the blood vessels in the brain to constrict (narrow). Smoking also stimulates the nerves in the back of the throat, contributing to headache pain.
Usually, by removing the stimulus (nicotine), headaches will be relieved. Quitting smoking or reducing exposure to second-hand smoke is especially helpful for those with cluster headaches. In one study of people with cluster headaches, those who reduced their tobacco use by less than one-half pack of cigarettes per day found their headaches decreased by 50%.
Migraines are often accompanied by stomach problems. In fact, eight out of every 10 people in the U.S. who are diagnosed with migraines report that their headaches cause nausea.
Migraines are the type of headache most likely to make you nauseated. There are, though, other causes of head pain that can also result in an upset stomach. It's important to consult a doctor about your symptoms. Your doctor can determine the cause and the appropriate treatment for your headaches and nausea.