It depends on the situation. For cats with mild symptoms, they usually recover within a week. However, if the condition is more severe, they may die within a week. This is mainly because onions contain n-propyl disulfide, which can damage a cat's red blood cells, potentially causing anemia, kidney damage, or even kidney failure, and in severe cases, death.
Generally speaking, if a cat is poisoned by eating onions, it will show symptoms such as lethargy, loss of appetite, foaming at the mouth, pale or cyanotic mucous membranes, and may even go into shock or die. Therefore, if you find that your cat has these symptoms, it is best to take it to a veterinary hospital for examination as soon as possible.
