I just wanted to add in here. Swansons has a certified PA free brand of Butterbur that I have been taking with no complications. I quit my Verapamil in Oct of last year and my migraine specialist who knows I like to stay as natural as possible told me about petadolex but also said to look around and talked about the PA’s, etc. Since being on butterbur (not religiously, but when I can remember it) I have only been dealing with migraines during “that time of the month”… so they have only been hormonally influenced. Other wise, no migraines! Still dealing with a lot of other symptoms, but at least I am pain free.