Most people rightfully believe that fruits are part of a healthy diet - but that only applies to humans. Grapes are small enough to seem like a viable treat or snack, because they're packed with flavor and low in calories, but they pose a real threat to dogs.
Grapes contain a toxin that leads to liver damage and kidney failure in canines, and for some it only takes a handful of grapes to do them in. Symptoms to watch for include excessive thirst and urinations along with vomiting and diarrhea. The actual toxic agent in grapes has yet to be identified, but researchers believe a mycotoxin might be to blame.
5. Macadamia Nuts