Of course, the odd doctor gets sucked in to the world of cigarettes and cigars.
But most don't.
Why? Because they understand the science, the dangers of smoking to your health? Maybe.
But most medics stay clear of tobacco because they see what the product does to their patients.
And not just doctors. Today we reveal the stories of NHS workers - nurses, porters - who have been inspired to stub out their cigarettes by what they see on wards.
Take June Burrows. She is an auxilliary nurse at the Beatson, the specialist unit for cancer at Gartnavel, who helps heal those with respiratory problems.
Seeing her patients was reason enough for her to quit.
Giving up smoking isn't easy - even if you desperately want to.
But it is an awful lot easier than it used to be. And you never have to try and quit on your own.
Our Clear the Air campaign is designed to underline just how much help is out there.
And not just gum and patches to ease those nicotine pangs
There are helplines and smoking cessation workers and other support - even if you are one of those increasingly rare doctors or nurses with a secret habit.