The ASPCA educates that grapes and raisins are fruits that are toxic to dogs. Avocado and moldy fruits can also be toxic to dogs. The website DogHeirs says that particular types of fruit seeds and pits are toxic to dogs as well.
Grapes or raisins, according to the ASPCA, can cause kidney failure. While in some cases dogs can eat a small quantity and go unharmed, in other cases, grapes or raisins are immediately toxic. Dogs that experience toxicity become lethargic and start vomiting. Kidney failure may follow, and some dogs that survive have kidney disease afterward.
Moldy fruit may develop toxins within, also per the ASPCA. In turn, those toxins can be harmful to a dog, causing muscle tremors which can lead to death if left untreated.
Avocado, says the ASPCA, contains persin, which is a substance toxic to dogs. Eating any part of the avocado can cause stomach discomfort, and the pit itself can cause blockage in the gastrointestinal tract. Though it can cause stomach pain, the ASPCA advises it does not cause serious illness. Avocado meal is sometimes contained in some pet foods and is not toxic.
PetHeirs says that persimmon seeds can cause enteritis, with diarrhea and fevers. The seeds and pits of apples, peaches, cherries and plums have cyanide, which can trigger intestinal obstruction and other symptoms. Vomiting, abdominal pain, lack of appetite, dehydration and shock are among them.