Is shisha bad for your health?

I've heard that one Shisha session is the equivalent of smoking 50 cigarettes. I could be wrong because my source isn't 100% reliable, but there you go. Breathing any burnt substances into your lungs obviously can't be good for you, so of course it's bad for your health. We all know the dangers of smoking cigarettes, so smoking something 50x as potent is just . . . Wow.