No aspirin for kitties... Their kidney's can't process it.
Never give a cat aspirin or any pain reliever without the vet prescribing what is the proper medicine. If you think your cat is ill, then you need to take it to the vet. Hope this helps, good luck.
Please do not give your kitty any aspirin or tylenol or anything of that nature. There is only one pain medication that is safe for kitties and it must be prescribed by the vet. Cats are easily poisoned by many many medications.