Acetaminophen is the active ingredient in Tylenol and some other related medications that are used to treat pain and fever in people. Unfortunately, this drug can be extremely toxic (poisonous) to dogs. Acetaminophen toxicity occurs when a dog swallows enough of the drug to cause damaging effects in the body.
Acetaminophen is mostly metabolized (broken down and eliminated from the body) by the liver. Some of the substances that are created during this process can have harmful effects on dogs.
The effects of acetaminophen poisoning are quite serious, often causing non-repairable liver damage. Dogs will typically experience acetaminophen toxicity at over 75 mg per kg body weight. The most common symptoms that may be noticed in pets suffering from acetaminophen toxicity include:
Brownish-gray colored gums
Swollen face, neck or limbs
Hypothermia (reduced body temperature)
Jaundice (yellowish color to skin, whites of eyes), due to liver damage