Is bribery not common practice in the health service?
It is usually more subtle than just an envelope full of banknotes. As maf says, things are changing, but I've certainly had experience of doctors encouraging patients to visit them privately, with the implication that they will be moved higher up the list for treatment.
I had a very strange experience a couple of years ago. Not wanting to wait months for an appointment with a dermatologist, I decided to pay 100PLN for a private consultation. Time was tight and I expected to be seen at the appointed hour. I was kept waiting for 40 mins, and when I finally saw the doc I politely complained that I had gone private because I didn't want to be kept waiting. He got pretty angry, slapped my 100PLN note down on his desk and threw me out. It was hilarious. In my youth I was kicked out of a pub or two, but I never expected to be ejected from a doctor's surgery.