Milk is listed as a food/drink unsafe for cats, this is because many cats have an intolerance to lactose which can cause gastrointestinal upset. Some cats can consume small amounts of milk.
Liver is another sometimes food as it contains high levels of vitamin A which can be toxic to cats.
Raw bones can be a great way to keep your cat’s teeth clean, but cooked bones become too brittle and can cause severe damage to cats.
Chocolate contains both theobromine and caffeine both of which are central nervous stimulants. The darker the chocolate, the more toxic.
Onions and garlic should be completely avoided, they contain oxidative substances which cause Heinz body anemia in cats. Even a small amount of onion can be enough to cause death.
Cats are obligate carnivores, meaning they have to consume meat to meet their nutritional requirements. A vegetarian or vegan diet is completely unsuitable for cats. Some raw or cooked vegetables such as pumpkin can be given to cats as an occasional treat, but meat should be the predominant part of your cat’s diet.
Other foods cats should avoid include fatty foods which can cause pancreatitis (as well as obesity), cherry seeds, yeast, macadamia nuts, and apricots.