poisoning with pain medications is common. aspirin, paracetamol/acetaminophen (tylenol), ibuprofen (advil), and naproxen (aleve) can all cause severe clinical signs in dogs, including vomiting blood, diarrhea, and abdominal pain. specifically, aspirin can cause metabolic acidosis and bleeding disorders, acetaminophen can cause liver disease at high doses (the toxic dose is 150 mg per kilogram of body weight), ibuprofen can cause kidney disease, and naproxen can cause ulcers in the stomach, which can perforate. treatment depends on the clinical signs and often involves inducing vomiting, gastric lavage, intravenous fluid diuresis, and supportive care. the antidote for acetaminophen toxicity is n-acetylcysteine.