He was distrustful of doctors for the course of his life, and subscribed to herbal/folk medicines. The reason why he funded so much medical science is mostly that Frederick T. Gates, the manager of his philanthropic affairs, managed to persuade him to do so.
Being distrustful
of doctors is still largely a winning strategy, depending on the area that you distrust them in. Regardless, blind obediance to the dictates of your local GP is a good way to find yourself in a pine box.