* Tulip bulbs contain toxic alkaloid and glycoside compounds which is why, even if they’re not going to kill you right away (probably), you’re not exactly doing yourself a favour by eating them either.
During the last year of World War II however, tulip bulbs despite being toxic to humans were a crucial source of food, helping people in the Netherlands get through times of famine, especially in the winter of 1944/45. They were grated into flour and baked into small loaves of bread, used to make soups or simply boiled.
As for the petals: I was surprised to find quite a lot of recipes where they were either stuffed (with a savoury or sweet filling) or used in salads. I’ve never had tulip petals myself and honestly (call me small-minded if you want) I’m not particularly tempted to give them a try any time soon. ;)