Causes of headaches: Food, Chemicals, Drugs, Additives and Alcohol
Many substances can cause headaches, and these include chemical solvents, gas appliances, alcohol, certain foods, additives and preservatives, car fumes and drugs, both prescribed and over-the-counter varieties. Sometimes the headaches are caused by the sudden withdrawal of a substance to which you're addicted -such as caffeine; a food to which you're allergic; or one of the addictive drugs. In each case, the treatment is obvious - identify the problem, and then permanently eliminate the offending substance.
Some of the reactions we get to chemicals are caused by a direct effect of the chemical on the body. The effect may be related to the dose we receive - a pharmacological response. In other cases the reaction is allergic. This works by a completely different pathway, with the offending substance triggering off the body's immune system. In this case you get a maximum response for anything other that the tiniest dose.
Although pharmacological and allergic responses work through completely different routes, treatment is much the same. The only difference between the two is that it will be harder to completely remove something to which you are allergic, because even tiny amounts of the offending chemical may trigger symptoms.
Let's look at some of the more common sources of chemicals that can cause headaches.
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MISCELLANEOUS Causes of headaches: The Body Clock