A friend's friend's child had that reaction to spicy food. From then on, when the parents didn't want the child to have something they'd tell her, "You won't like it - it's spicy."

Chocolate? "Ywliis"
Candy? "Ywliis"
...

Of course, eventually the child will grow up enough to experiment and will never trust the parents again, but for a while it works well.

Cheers,
Scott.