There is a big list of toxic plants and fruits, some more exotic than others. You should pay particular attention to the more common toxic foods that you can find around the house.
The stem, seeds and leaves of the apple, almond, apricot, peach, wild cherry, prune and similar fruits can cause diarrhea, vomits and pain to the dog. The seeds contain cyanide lethal to dogs.
Avocados, chocolate, mushrooms, nutmeg, tobacco, onion and raw eggs should never be given to a dog. Among other things, like vomits, nausea, tremors, they can cause severe intoxications to the dog that may lead to death.

