It is not safe to give a dog human formulations containing acetaminophen, the active ingredient in Tylenol. Sometimes a vet will prescribe an appropriate dosage of acetaminophen for a dog. Give a dog this medication only under a vet's direction, states Vetstreet.
Acetaminophen toxicity can harm or kill a dog. It can cause liver damage and potentially liver failure and can also prevent red blood cells from carrying oxygen, states Vetstreet
Should a dog ingest acetaminophen, vomiting should be induced immediately if possible, according to Vetstreet. Either way, the dog needs to be taken to a veterinarian for evaluation and any necessary care. This may involve neutralizing the drug if it is still in the stomach or administration of an antidote. Other measures may also be required to save the dog.