How much garlic is toxic for cats?

Garlic is more concentrated and highly toxic than onions. Even a small amount of garlic could cause toxicosis in cats. Fresh or powdered garlic should be kept away from cats.

What is toxic to cats?

Salt, onions, scallions, and garlic are very toxic to cats. When eaten in large quantities, these foods can cause damage to the red blood cells of a cat. Onion and garlic powder can also cause feline anemia