A friend cooked up some older potatoes out of the bottom of her fridge and actually made herself and her husband mildly ill for a day. I’d heard this about green potatoes but never actually known it happen until then.
When my horses come down sick and have a fever and will not eat, I always give them watermelon. This is never refused, they get a little in their bellies and it helps to hydrate them. I always call the vet first.