True story. Once upon a time long ago my grandmother would not eat pork. My aunt cooked a porkloin or something and represented it as something else. A dirty trick as it turned out and one that she regretted too late.
My grandmother ate it and told my aunt it was delicious. When my aunt told her it was pork my grandmother got ill threw up and had a few days in bed trying to recover from it. She never forgave my aunt.
Now the meat wasn't poison but her mind reacted as if it were. Her mind took over and caused her body to suffer for it.
Slartibartfast 