Aspirin (acetylsalicylic acid) is a common over-the-counter (OTC) nonsteroidal anti-inflammatory drug (NSAID). It’s also a salicylate, which is a chemical found in plants and used in many pain-relieving drugs.

Aspirin is available in generic and brand name equivalents, with Bayer and Anacin being two common brands. There are also many medicines that contain aspirin along with other drugs to treat different types of pain. These include Alka-Seltzer, Excedrin and Supac, among others.

Non-Prescription Uses of Aspirin

Like ibuprofen, aspirin is often used to relieve mild to moderate pain and to reduce fevers.

As an NSAID, its main function is reducing pain by decreasing swelling.

Conditions that are often treated with aspirin include:

  • Headaches
  • Period pains
  • Arthritis
  • Cold symptoms
  • Toothaches
  • Muscle pain

Some people take aspirin as a daily medication to lower the risk of heart attack or stroke. This is common among people who have personal or family histories of these medical issues. If you think you may need to start a daily regimen of aspirin as a preventative measure, talk to your doctor.

Aspirin can also help treat heart attacks as they are being experienced. If you think you may be having a heart attack, quickly take a regular-strength aspirin by chewing it and swallowing with water. Chewing the pill will help the drug to enter your system faster and start clearing the blood clot. You should also seek immediate medical attention.

Prescription Uses of Aspirin

Although it is available as an OTC drug, aspirin can also be prescribed for daily use. It is often used by those with chronic conditions to minimize pain and overall swelling. These conditions will often come with a treatment plan that includes other drugs besides aspirin.

Doctors may prescribe aspirin to help treat:

Rheumatoid arthritis: Rheumatoid arthritis is a chronic autoimmune disorder that causes the body’s immune system to attack its own tissues. This leads to pain and swelling in the joints.

Osteoarthritis: Osteoarthritis is a type of arthritis caused by the “wear and tear” in the joints. This leads joint cartilage to thin, triggering swelling and pain.

Lupus: An autoimmune disease, Lupus makes the body attacks itself and causes a number of serious symptoms. These include pain, headaches, anemia, rashes, hair loss, and other serious diseases.

Other rheumatologic conditions: Other conditions that aspirin may be prescribed to treat pain and swelling, or clotting issues include bursitis, Crohn’s disease, gout, scleroderma, and more.

How Aspirin Works

Never take more than 4,000 mg of Aspirin in a 24-hour period.

Aspirin comes in many forms. It can be purchased as a regular oral tablet, a delayed-release pill that waits to release medication to protect the stomach, a chewable tablet, powder, or a suppository (a pill that is taken rectally). The prescription version is an extended-release, or long-acting, tablet taken by mouth.

Aspirin works by blocking the production of prostaglandins (enzymes that cause swelling). The drug also acts as an anticoagulant, preventing platelets from clotting to reduce the risk of heart attacks and strokes. This can increase bleeding risks for patients taking blood thinners, so check with your doctor if you take medications like Pradaxa or Xarelto, before taking aspirin.

It’s important to follow the directions on the aspirin bottle or packaging carefully to ensure you adhere to the right dosage. Nonprescription aspirin can be taken every four to six hours as needed. The maximum dose of aspirin that an adult should take in a 24 hour period is 4,000 milligrams (mg).

When taking aspirin orally, always swallow pills with a glass of water. If the tablet is intended for extended-release, be sure not to break, crush, or chew it, as this can lead to unwanted side effects.

Side Effects of Aspirin

Aspirin can occasionally cause side effects. While these will usually go away on their own, call your doctor if you experience severe or persistent adverse effects while taking aspirin.

The most common side effects of aspirin include:

  • Nausea
  • Vomiting
  • Stomach pain
  • Heartburn

In rarer cases, aspirin can cause more serious side effects. Long-term use of high-dose aspirin can lead to gastrointestinal (GI) bleeding, and the drug should not be taken if you have a history of GI bleeding. Seek immediate medical attention if you experience serious side effects while taking aspirin.

Serious Aspirin Side Effects
  • Hives or rash
  • Swelling of the face
  • Difficulty breathing
  • Fast heartbeat
  • Bloody vomit
  • Stools that are bloody or black
  • Loss of hearing

Serious side effects can be caused by allergies to the drug. If you suspect you may be allergic to aspirin, stop taking it immediately.

Aspirin Overdoses

Aspirin overdoses can lead to serious, long-term health problems, and can be fatal. It’s important to follow the directions on the packaging and never exceed the recommended dosage to avoid an accidental overdose. If you suspect you may be experiencing an overdose or notice the warning signs in someone else, seek immediate emergency medical attention.

Warning signs of an aspirin overdose
  • Severe vomiting
  • Fever
  • Restlessness
  • Dizziness
  • Double vision
  • Shaking
  • Confusion and jumbling of words
  • Hallucination
  • Fainting
  • Seizures

Unfortunately, some aspirin overdoses are not accidental. If you are having suicidal thoughts, or are worried that someone you love may be contemplating suicide, contact a suicide prevention helpline at once. If you are feeling suicidal, or suspect that someone you love may be, contact a suicide prevention helpline immediately.

Call 1-800-273-8255 to speak with the National Suicide Prevention Lifeline

Who Should Take Aspirin?

Aspirin is a relatively safe painkiller that can be found in many households across the U.S. Children over the age of two can take the drug, but pay attention to the appropriate dosage for their age, since children cannot take as much aspirin as adults.

Although aspirin is mostly safe for kids, children and teens who are in the process of recovering from chickenpox or flu-like symptoms should not take the drug, as it has been known to cause Reye’s syndrome. This condition is rare but serious, and can cause swelling in the liver and brain.

Studies have shown that taking aspirin regularly while pregnant can lead to birth defects and increase your risk of miscarriage. If you are pregnant or trying to conceive, talk to your doctor before taking aspirin.

Aspirin Lawsuits

Aspirin products have been the subject of several lawsuits. In 2013, Bayer was at the center of a class action lawsuit for consumer fraud after advertising the health benefits of two combination aspirin products that had not been approved by the U.S. Food and Drug Administration (FDA). These products were eventually found to be unhealthy when used for a long time. Faced with allegations of false advertising, Bayer settled for $15 million.