Some estimates suggest that 25 percent of the population has a headache right now. Because headaches are so common, most people think it is a normal part of life. Headaches, however, are a sign that something is wrong. We know that stress, toxic fumes, certain foods and preservatives, and even alcohol can cause headaches. A frequent and overlooked cause of headaches is the malfunction of spinal bones in the neck and upper back. When the bones of the spine lose their normal position or motion, the sensitive nerves and blood vessels to the head become compromised. When these delicate tissues are stretched or irritated, they can produce certain types of headaches. While aspirin or other medications may cover up the symptoms, they do not really correct the cause of the headache. A report released in 2001 by researchers at the Duke University Evidence-Based Practice Center in Durham, NC, found that chiropractic adjustments resulted in almost immediate improvement for those headaches that originate in the neck, and had significantly fewer side effects and longer-lasting relief of tension-type headache than a commonly prescribed medication.