Aspirin Versus Acetaminophen

The two most common over-the-counter pain medicines are aspirin and acetaminophen. Although both are about equally effective for treating mild aches and pains, there are circumstances where one drug is a safer and more effective choice than the other. Let's see how they compare.


Aspirin, also known as acetylsalicylic acid, is a non-steroidal anti-inflammatory drug that is used to treat headaches, minor aches and pains, and inflammation. It is also sometimes used to treat or prevent heart attacks, strokes, and angina. Aspirin works by inhibiting the production of prostaglandins, hormone-like body chemicals that are necessary for blood clotting and which also sensitize nerve endings to pain. Ibuprofen works in a similar manner.

Acetylsalicylic acid is derived from salicylic acid which in turn is derived from salicin, a naturally occurring compound that is found in the bark and leaves of willow trees. Natural medicines made from ground up willow bark and leaves have been used since at least the time of Hippocrates over 2000 years ago to treat headaches, pain and fevers.

Chemists at Bayer AG produced a synthetically altered version of salicin in the 1890's that was easier on the stomach than pure salicylic acid. This new "buffered" drug, formally acetylsalicylic acid, was named Aspirin by Bayer AG. The word "Aspirin" is derived from acetyl and spirsäure, an old German name for salicylic acid. By the turn of the 20th century, Bayer was selling Aspirin worldwide.


Acetaminophen, also known as paracetamol or N-acetyl-para-aminophenol, is used to relieve aches and pains and also to reduce fever. The drug was first marketed in the U.S in 1953 by Sterling-Winthrop Co., which promoted it as preferable to aspirin since it was safer for children and people with ulcers and other gastric conditions.

Acetaminophen is in a class of medications called analgesics (pain relievers) and antipyretics (fever reducers). It is the most widely used pharmaceutical analgesic and antipyretic agent in the United States and the world. Acetaminophen is best known by the Tylenol brand but there are also many generic versions available.


Aspirin is a better choice than acetaminophen for treating inflammation because the latter has no anti-inflammatory benefits. Aspirin is also more beneficial as a preventive treatment for heart attacks and strokes - an attribute that is responsible for a big uptick in aspirin sales in recent years after the drug's popularity declined after the market releases of paracetamol (acetaminophen) in 1956 and ibuprofen in 1969.

Unlike aspirin, acetaminophen doesn't irritate the lining of the stomach. For those with acid reflux (heartburn), ulcers or other digestive tract issues, acetaminophen is generally a better choice than aspirin. It is also considered safer for hemophiliacs and children. Acetaminophen is the drug of choice for lowering fevers in children.

Although acetaminophen lacks the anti-inflammatory properties of aspirin, if the pain is not due to inflammation, acetaminophen is as effective as aspirin.

Side Effects

For people with sensitive digestive systems, aspirin can cause an upset stomach, nausea, heartburn and even dyspepsia. And because aspirin is an anticoagulant, it is not a good choice of medicine for hemophiliacs and pain relief after a surgical operation. Aspirin should not be given to a child or teenager who has a fever, especially if the child also has flu symptoms or chicken pox. It can cause a serious and sometimes fatal condition called Reye's syndrome in children.

Although acetaminophen is considered by many to be the safest over-the-counter pain reliever, it can cause severe liver damage if taken in excess of the recommended doses. The potential for acetaminophen to harm the liver is increased when it is combined with alcohol or drugs that also harm the liver. Doctors warn that it’s easier to overdose on acetaminophen than aspirin.