There's an old saying: "The only thing more foolish than listening to your doctor is not listening to your doctor."
Nassim Taleb says those things can be reconciled by taking responsibility for your own health while you're well and not listening to the doctor (many of whom are more concerned about not getting sued than your well-being), but listening to your doctor very carefully if you're ill (e.g., you've had a heart attack).
Steven Levitt, of Freakonomics fame, was recently interviewed on Econtalk. At approximately minute 21:50, he said that, if you're diagnosed with a rare disease, you can research it for a day on the Internet and you'll know more about it than a general practitioner.
He said it for humorous effect, but he was very serious.