Every time i need red onion get a headache, why? I know lots of other people that suffer the same from eating red onion. i dont get a headache from eating a normal white onion. so why is it? is a chemical or something in the red onion that makes me get a headache? i dont get a headache from eating any other food and am not allergic as far as i know.

Could be an allergy. I know several people with such and one of them actually can go into shock and die.

so..stay away from them. You body is telling to not eat them simple dont eat red onions... . lol ;) if you want a headache buy Budweiser... . g`tee headache in a tin ;) you have an allergy to red onions,you should leave them off.