I can't eat mushrooms because I am allergic to them. But... aside from stuff that isn't actually considered food (like brains) not counting, and sticking to the topic of actual food. Anchovies and Sardines.
But. More than most things that end up on my list of, "I won't touch that crap, let alone put it in my mouth and swallow" is...
Miracle Whip! <--- Some of the grossest stuff I've ever tasted.
It must be Duke's. If it isn't Duke's, then damnit, get some BBQ sauce or something. If you absolutely have too, Hellman's is acceptable. In an emergency. But it's Duke's Mayo FTW. Anyone who says otherwise is Blaspheming.