Garlic can be fatal to dogs due to a compound called thiosulfate that damages red blood cells. It takes a lot of garlic to cause toxicity, but some breeds are particularly sensitive.
Vitamins containing iron can be toxic for dogs, as they can damage their digestive system wall lining, kidneys, and liver.
Avocados are harmful because of persin, a fungicidal toxin. Smaller amounts can cause vomiting and diarrhea, but only excessive dosages are deadly.
Small doses of mustard won't kill dogs, but high levels are hazardous. Vets commonly recommend mustard to induce vomiting due to its moderate toxicity.
The flesh of apples is not toxic, but the seeds can be poisonous due to a compound called amygdalin. However, they have to be consumed in large quantities and chewed to be toxic.
Giving your dog a raw, uncooked bone to chew on is great, but avoid cooked bones. These can easily splinter and in large quantities cause constipation or perforation, which can be fatal.
Because fermenting yeast quickly enters the system and creates enough ethanol to cause alcohol poisoning, feeding your dog unbaked dough is unsafe.
Nutmeg contains a compound called myristicin, which, when ingested by dogs in large quantities, can lead to rapid heart rate, hallucinations, and seizures.
Chocolate contains a stimulant called theobromine, which is poisonous to dogs. The amount of theobromine depends on the type of chocolate.
Onions can be poisonous to dogs due to the thiosulfate they contain. Certain dog breeds are more vulnerable, and their size makes a huge difference.