If you are a large consumer of beverages containing caffeine, it can produce headaches as a "withdrawal" symptom.In my case, it produced IBS symptoms as well. This, IMHO was a food intolerance and/or allergy. Some other foods, particularly certain white wines, also produce headaches for me.Headache is a common side effect from many different types of drugs, so if you are taking a prescription, it could be the culprit.Since food allergy/intolerance is a touchy subject on the board, here is my disclaimer.___________________________________________My symptoms are not necessarily the sameas your symptoms. Effective treatments for me are not necessarily the same for you.Your mileage may vary.___________________________________________