Marjorie, In the case of aspirin, I believe we got this medication based on our own Indian tribes observation that the bark of willows worked when boiled and its juices drunk as a pain reliever. Many of our earlier meds were tried and used * if they survived* by the original inhabitants of various countries. I am sure no one would argue this fact whether the medical establishment knows why it works or how is immaterial. If this particular one doesnt work for you , it does for most of us and it certainly does for my headaches. Sincerely, *seattle* Audrey