My cousin once told me when I was 7 that broccoli stems were poisonous and that you'd die if you ate them.
I am quite happy to have been told this by my mother, that they are indeed, not poisonous.
A childhood belief about dangerous food

others believed things like this
- My older sister told me squirrels were poisonous, and I believed her until I was 9.— Jenni
- that the green bit of cucumbers was poisonousAnon
- I used to believe that the dust on top of doors was poisonous.— draconid
- Dark brown Smarties were poisonous.Anon
- I used to think if a tornado sucked up a poisonous mushroom, it would die.— Will
- My mum used to tell me that you couldn't drink water out of the tap from the bathroom as it was poisonous.Anon