1. Milk
Many dogs are lactose intolerant. If your dog develops farting, diarrhea, dehydration or skin inflammation after drinking milk, you should stop feeding milk. Dogs who are lactose intolerant should consume lactose-free milk (goat milk is generally recommended).
2. Avocado (avocado)
Avocado contains a substance called persin, which is toxic to most dogs. Dog food that dogs usually eat is called avocado dog food. Don’t let your dog eat avocado just because you think avocado is good for hair. Dog food only extracts the hair-beautifying ingredients in avocado. As for avocado, it is not good for dogs. It's edible, but keep it away from your dog.
3. Onions
Eating onions in any form can lead to onion poisoning. Onion poisoning can cause rupture of red blood cells in dogs, weight loss and depression.
4. Coffee
Coffee and coffee products contain a chemical called methylxanthine. When dogs ingest it, it can cause dehydration and vomiting. Excessive consumption can lead to death.
5. Broken bones
Broken bones, such as chicken bones, may pierce the dog’s throat; or cut the dog’s mouth, esophagus, or stomach or intestines. If you want to feed bones, cook them in a pressure cooker. Bone marrow is an excellent source of calcium, phosphorus, and copper. Chewing large bones can help remove tartar.
6. Raw or cooked liver
A small amount of liver is good for dogs, but too much liver may cause problems. Because the liver contains a large amount of vitamin A, it can cause vitamin A poisoning. About three chicken livers (or corresponding amounts of other animal livers) a week can cause bone problems.
Reference: Baidu Encyclopedia-Dog