We humans are accustomed to popping an aspirin (or some other over-the-counter pain reliever) for various aches and pains, and some cat owners foolishly give these human medications to their pets. In fact, some of these medications can be given to cats, but it isn’t wise to do so without consulting a vet.
Human dosages and cat dosages are (to state the obvious) very different, plus a cat metabolizes medications at different rates than humans do. Practically every vet has had to treat a cat for aspirin poisoning. The upshot: “Just say no” to administering human medicines to a cat.