5 Foods, You Should Never br Give Your Dog.br It's important to know br what NOT to give your dog.br 1. Garlic and Onions.br Both of these foods contain thiosulphate, which damages dogs' red blood cells br and can lead to anemia.br 2. Avocado.br Avocado contains a toxin called persin, br which can cause your dog to br develop intestinal issues.br 3. Macadamia Nuts.br Though some nuts are okay to give br to your dog, macadamia nuts contain br a toxin that can be harmful to your br furry friend's nervous system.br 4. Chocolate.br Most people already know this one, br but it bears repeating. br Chocolate is highly toxic to dogs.br 5. Grapes and Raisins.