I used to believe that if you accidentally ate grape pips you 'd get appendicitis.
A childhood belief about seeds

others believed things like this
- I used to believe that if you ate the pips in apples a tree would grow inside your stomach.— QueenB
- I used to believe that if you ate a grape upside down it would come out your nose.— Cath
- My dad always told me never to swallow the pips from apples because trees would start growing in my stomach!!— ALISON W
- We were told at school by the evil dinner ladies that apple pips contained arsenic.....Anon
- I used to believe that if you soaked a raisin (or prune) in water, it would turn back into a grape (or plum).— C.C.
- I thought that grape juice was called "great juice". Anon