I just cannot handle the taste of black licorice in any form, anise, whatever.
It gives me a physical reaction immediately if tasted accidently....yecch.
The other thing that I will not eat is liver of any kind, beef, chicken, no way.
I guess also you could include any organ meat, though I have never had anything but liver, the idea of eating something's brain (or kidneys or heart, etc) just makes me want to vomit.

And bugs. I will not ever knowingly eat a bug served to me (though my mom tells me I used to eat ants when I was a kid, but I gave it up when I was 3), like a grasshopper or crickets or grubs or anything like that. No thank you. I had a co-worker a few years ago who was very adventurous and signed up for a "Cooking with Bugs " class. He came back and told us in glowing terms how yummy all the stuff was....and maybe it was, but we never let him sign up for any pot lucks after that.

I never buy, order or eat veal either, but thats more of a personal choice. I grew up liking lamb because my grandmother would make it a lot, but one day my oldest son (who is 8) overheard me talking about cooking some and burst into tears, crying out, "thats not fair-those lambs never hurt anyone-they are just LAMBS! You can't eat lambs!".
Made me cry too, and I haven't mentioned it since.

Beyond those things, not a picky eater.