Many pet owners wonder whether it's safe to dispense over-the-counter, "people" medicines to their cats and dogs. The fact of the matter is, some human medications such as Tylenol (acetaminophen) can be toxic, and even lethal to pets. Pound-for-pound, doses for animals are not always the same as for people. You could very easily overdose or underdose your pet. In addition, your pet may have a medical condition which could be worsened by the use of some human medications. As a rule, you should never use over-the-counter human medications on your pet unless you are advised to do so by your veterinarian. If your veterinarian does prescribe them, be sure to follow the dosage instructions exactly as written.