Paracetamol (also known as acetaminophen) is a common over-the-counter drug used to relieve mild to moderate pain and reduce fever, sold under brands like Tylenol and Panadol. It works well for tension headaches and pain after wisdom tooth removal, though it is less effective than ibuprofen, and its benefits for osteoarthritis, back pain, and cancer pain are considered small or unproven. While generally safe at the recommended adult dose of 3 to 4 grams per day, chronic use or overdose can cause severe liver damage, making paracetamol poisoning a leading cause of acute liver failure in many countries. First synthesized in 1878 by Harmon Northrop Morse, it is on the World Health Organization's List of Essential Medicines and is the most widely used pain and fever medication in the US and Europe. Interestingly, its use for fever is debated—studies show it barely lowers temperature in critically ill patients without improving survival, and it offers no benefit for dengue fever, sometimes even raising liver enzyme levels. Nevertheless, it remains the first-line treatment for pain and fever in pregnancy, as untreated conditions can harm both the mother and the developing fetus.