Difference Between Acetaminophen and Aspirin (With Table)

Everyone deals with fever and aches now and then. They are an indispensable part of life. Drugs and medication help to solve these problems. Two of the most common ones used are acetaminophen and aspirin. Both of them relieve mild pain but are very different.

Acetaminophen vs Aspirin

The main difference between acetaminophen and aspirin is that acetaminophen is an antipyretic and analgesic drug. This means that it reduces fever and acts as a painkiller too. On the other hand, aspirin is a Nonsteroidal Anti-Inflammatory Drug. It can relieve mild pain and also reduce inflammation.

Acetaminophen is also known as paracetamol. It is known for its properties to relieve pain and also reduce fever. Tylenol is the brand name that has acetaminophen as an active ingredient. The name acetaminophen is used in the US. Paracetamol is the alternate name for Britishers. Also known to be helpful during dengue fever.

Aspirin is a Nonsteroidal Anti-Inflammatory Drug. It prevents the clotting of blood and relieves pain. It can be used for varied purposes. Some of them are toothache, headache, arthritis. It cannot be used during dengue fever as it may cause bleeding. It can help to prevent heart attack.

Comparison Table Between Acetaminophen and Aspirin

Parameters of ComparisonAcetaminophenAspirin
Drug typeAnalgesic/AntipyreticNonsteroidal Anti-Inflammatory Drug
Blood-thinning propertyIt doesn’t help in thinning the blood.It helps in thinning the blood.
Chemical formulaC8H9NO2 C9 H8O4
UsesFever reducer, a painkiller.Reduce Inflammation, arthritis, preventing heart attack by thinning the blood.
Side effectItching, constipation etc.Drowsiness, upset stomach, abdominal pain.
Effect on liverCan cause liver damage.Known to cause less damage than acetaminophen.
Dengue feverHelp reduce fever and pain during dengue.Should not be used during dengue fever. It is dangerous and can cause bleeding.
Use during pregnancyIt is the initial choice to treat pain during pregnancy.It should not be taken during pregnancy.

What is Acetaminophen?

Acetaminophen belongs to the analgesic and antipyretic category of drugs. It is known for its pain-relieving and fever reduction properties. It is known by other names like Tylenol and Paracetamol.

Acetaminophen is a generic name used in the US. Paracetamol is used by British. Tylenol is the brand name in which acetaminophen is an active ingredient. It is used for the treatment of acute migraine, fever, body ache. It is known to cause liver damage and should be taken on prescription.

It is the safest choice and is used to treat pain during pregnancy. Even a breastfeeding mother can use it. It shows no harmful effect on the health of the baby and mother. It is also known to ease menstrual cramps.

Some side effects of using this medicine, that is faced are headache, vomiting, constipation, nausea, itching and insomnia.

What is Aspirin?

Aspirin or acetylsalicylic acid has pain-relieving properties. It is anti-inflammatory. It reduces the chances of demise due to cardiac arrest. It thins the blood and lowers blood pressure. It proves to be useful in a lot of treatments.

Some of the problems like toothache, headache, joint pain, dysmenorrhea can be relieved by using aspirin.

It is known to cause an antiplatelet effect. This means that it stifles the action of platelets. It is not recommended to take it during pregnancy. Alcoholic drinks are not safe while using this drug.
It can cause indigestion, bleeding and stomach ulcers.

Some side effects can be encountered after using aspirin.
These are gastrointestinal ulcers, indigestion, headache, upset stomach, cramps, abdominal pain and heartburn.

Main Differences Between Acetaminophen and Aspirin.

  1. Acetaminophen is a drug that belongs to the antipyretic/analgesic category of drugs. On the other hand, Aspirin is NSAID.
  2. Acetaminophen is not a blood thinner and cannot avoid blood clots whereas aspirin has this property.
  3. Acetaminophen causes liver damage whereas aspirin is known to be less harmful to the liver.
  4. The chemical formula of acetaminophen is C8H9NO2. The chemical formula of aspirin is C9H8O4.
  5. Acetaminophen is a painkiller and fever reducer but aspirin has anti-inflammatory properties.
  6. Acetaminophen can be used to treat the fever and pain caused by dengue but aspirin must not be used. It is rather harmful.
  7. Acetaminophen can be used during pregnancy whereas aspirin should not be used during pregnancy.
  8. Acetaminophen can be used for children during chickenpox for fever reduction. On the other hand, one must never use aspirin for chickenpox fever for children.
  9. Acetaminophen is considered safe for children but it is not recommended to give aspirin to children. It is rather for adults.


Both the drugs acetaminophen and aspirin are an important part of medication. They are used on large scale for treatment. Though, both of them are known for reducing mild pain yet they have a lot of differences.

They belong to a different class of drugs and have different target organs and mechanisms. They have varied side effects and must be used only on prescription/recommendation by a doctor.

Acetaminophen is an analgesic/antipyretic drug that is known to reduce fever and body pain. It can help during dengue fever. It is considered the priority during pregnancy and is safe for the mother and baby.

Acetaminophen is the common name used in US and Paracetamol is a name that is more likely to be used in India. It cannot thin blood and hence is not useful to prevent heart attack.

Aspirin is a non-nonsteroidal inflammatory drug that can reduce mild pain. It is known to cause an antiplatelet effect.

It is not recommended to use during pregnancy. Consuming alcohol and aspirin together can have serious consequences. It can prevent heart attack but, its blood-thinning properties can sometimes cause issues.

While acetaminophen can cause liver damage, aspirin is known to cause internal bleeding after prolonged use. Two of them are favourable for reducing pain.


  1. https://www.acpjournals.org/doi/abs/10.7326/0003-4819-87-2-202
  2. https://www.acpjournals.org/doi/abs/10.7326/0003-4819-104-3-390