Bill, actually within Canada, they do encourage that you tell your regular doctor everything that you are taking. In other cases if you are in an expermental case study, the doctor does have the right to say to you.... no do not use anything but what we are giving you. Mom was taking iressa and they have very rigid guidelines to what is allowed and what is not allowed. And yes there are always miracles that happen and I personal can vouch for a couple..... but they do not always happen.