Smoking can contribute to headaches for both the smoker and the nonsmoker. Nicotine, one of the compounds found in tobacco, has vascular properties which may contribute to headache. This occurrence is more evident in cluster headache patients. During a cluster cycle, reducing their use to less than one-half pack of cigarettes per day may be beneficial in controlling the headaches. The odor produced by burning tobacco products, and other scents, can trigger migraine in some susceptible individuals. Migraine is associated with an increased risk of stroke and this risk is amplified in smokers.