Garlic might be good for us, but dogs metabolize certain foods differently than we do. According to the Merck Veterinary Manual, garlic and other members of the allium family, including onions, contain thiosulfate, which is toxic to dogs but not to humans.
Studies have found it takes approximately 15 to 30 grams of garlic per kilograms of body weight to produce harmful changes in a dog’s blood. To put that into perspective, the average clove of supermarket garlic weighs between 3 and 7 grams, so your dog would have to eat a lot to get really sick. However, some dogs are more sensitive to garlic toxicity than others, and consumption of a toxic dose spread out over a few days could also cause problems.
Avocado No, dogs should not eat avocado. While avocado may be a healthy snack for dog owners, it should not be given to dogs at all. The pit, skin, and leaves of avocados contain persin, a toxin that often causes vomiting and diarrhea in dogs. The fleshy inside of the fruit doesn’t have as much persin as the rest of the plant, but it is still too much for dogs to handle.
Cherries No, dogs shouldn’t eat cherries. With the exception of the fleshy part around the seed, cherry plants contain cyanide and are toxic to dogs. Cyanide disrupts cellular oxygen transport, which means that your dog’s blood cells can’t get enough oxygen. If your dog eats cherries, be on the lookout for dilated pupils, difficulty breathing, and red gums, as these may be signs of cyanide poisoning.
Grapes No, dogs should not eat grapes. Grapes and raisins have both proved to be very toxic for dogs no matter the dog’s breed, sex, or age. In fact, grapes are so toxic that they can lead to acute sudden kidney failure. Definitely skip this dangerous treat.
Mushrooms No, dogs should avoid mushrooms. Wild mushrooms can be toxic for dogs. While only 50 to 100 of the 50,000 mushroom species worldwide are known to be toxic, the ones that are can really hurt your dog or even lead to death. Washed mushrooms from the supermarket could be OK, but it’s better to be safe than sorry; skip out on the fungi all together.
Tomatoes No, dogs should probably avoid tomatoes. While the ripened fruit of the tomato plant (the red part humans normally eat) is generally considered safe for dogs, the green parts of the plant contain a toxic substance called solanine. While a dog would need to eat a large amount for it to make him or her sick, it’s better to skip tomatoes all together just to be safe.
Matt Rountree wrote:Aside from onions and garlic, leeks and chives contain allium which is toxic for dogs.