Aspirin, or acetyl acid salicylic (ASA), is commonly used as a pain reliever for minor aches and pains and to reduce fever. It is also an anti-inflammatory drug and can be used as a blood thinner.

People with a high risk of blood clots, stroke and heart attack can use aspirin in the long term at low doses.

Aspirin contains salicylates derived from willow bark. Its use was first recorded around 400 BC, at the time of Hippocratic, when people chewed willow bark to relieve inflammation and fever.

It is often given to patients immediately after a heart attack to prevent further clotting and death of heart tissue.

Fast Facts

Here are some key points about aspirin:

  1. Aspirin is one of the most widely used drugs in the world.
  2. Comes from salicylates, which can be found in plants such as willow and bitter trees.
  3. Aspirin was the first non-steroidal anti-inflammatory drug (NSAID) to be discovered.
  4. Reacts to a number of other medications, including warfarin and methotrexate.

What is aspirin?

Aspirin is a non-steroidal anti-inflammatory drug (NSAID). NSAIDs are drugs with the following effects:

Analgesic: Relieves pain without anesthesia or loss of consciousness

Antipyretic: reduces fever

Anti-inflammatory: relieves inflammation when used in higher doses

Non-steroidal substances mean they are not stimulants. Steroids often have similar benefits, but can have undesirable side effects.

As analgesics, NSAIDs tend to be non-anesthetic. This means that they do not cause insensitivity. Aspirin was also the first antidepressant to be discovered.

Salicelles have been used in the form of willow bark for more than 2,000 years. Some people still use willow bark as a more natural treatment for headaches, aches and minor pains.

Aspirin in its current form has existed for more than 100 years. It remains one of the most widely used drugs in the world. It is estimated that about 35,000 metric tons of aspirin are consumed annually.

Aspirin is a trademark owned by German pharmaceutical company Bayer. The general term for aspirin is acetyl salicylic acid (ASA).


Aspirin is one of the most commonly used medications to treat mild to moderate pain, migraines, and fever.

Common uses include headaches, cycle pain, colds, flu, sprains and long-term conditions such as arthritis.

For mild to moderate pain, it is used alone. For moderate to severe pain, it is often used with other opioid analgesics and NSAIDs. At high doses, it can treat or help reduce symptoms:

1. Rheumatic fever

2. Rheumatoid arthritis

3. Other inflammatory joint diseases

4. Pericarditis

At low doses, it is used:

1. To prevent blood clots from forming and to reduce the risk of a transient ischemic attack (TIA) and unstable angina

2. To prevent myocardial infarction in patients with heart and vascular diseases by preventing the formation of clots

3. To prevent stroke, but not to treat stroke

4. For the prevention of colorectal cancer

Aspirin and children

Aspirin is not usually suitable for those under the age of 16, as it can increase the risk of Ray syndrome, which can appear after infection with a virus, such as colds, influenza or chickenpox. It can lead to permanent brain injury or death.

However, an aspirin specialist may prescribe an aspirin to a child under supervision if he or she has Kawasaki disease, and to prevent the formation of blood clots after heart surgery.

Acetaminophen (paracetamol, Tylenol) and ibuprofen are usually used instead.

Low dose of aspirin

A low dose of aspirin, 75-81 milligrams per day, can be used as an antiplatelet drug, to prevent the formation of blood clots. It can be given to the following patients:

  1. Surgery to graft the coronary artery
  2. Heart Attack
  3. Stroke
  4. Atrial fibrillation
  5. Acute coronary artery syndrome

People can also be given a low dose of aspirin if they have the following risk factors, and if the doctor believes there is a chance of a heart attack or stroke:

  1. High cholesterol levels
  2. High blood pressure
  3. Diabetes
  4. Smoking

Other people who may be recommended for a low dose of aspirin include:

  1. Sufferers of retinal damage or retinopathy
  2. People with diabetes for more than 10 years
  3. Patients taking high blood pressure medications

The U.S. Preventive Services Task Force (U.S.) currently recommends the use of low-cost daily aspirin to prevent heart, vascular and colorectal cancer in adults aged 50 to 59 who:

  1. They have a 10 percent or higher risk of cardiovascular disease
  2. Those who have no high risk of bleeding
  3. They are likely to live at least another 10 years
  4. Ready to take the dosage for at least 10 years

In all these cases, the individual will usually continue to take a low dose of aspirin daily for the rest of his or her life.


Aspirin is not recommended for individuals who:

  1. Peptic ulcer
  2. Hemophilia or any other bleeding disorder
  3. Known sensitivity to aspirn
  4. Allergic to any NSAIDs, such as ibuprofen
  5. At risk of gastrointestinal bleeding or hemorrhagic stroke
  6. Drink alcohol regularly
  7. Undergo dental treatment or surgery, no matter how small

People with the following conditions should be careful about taking aspirn, and should do so only if your doctor agrees:

  1. Asthma
  2. Uncontrolled hypertension
  3. Previous peptic ulcer
  4. Liver problems
  5. Kidney problems

Aspirin is not given during a stroke, because not all clots are caused by a clot. In some cases, aspirin can make stroke worse.

Anyone preparing for surgery should tell their doctor if they are taking aspirin regularly. They may need to stop taking aspirin at least 7 days before the operation.

Pregnant or nursing patients may take a low dose of aspirin, but only under the supervision of a doctor. A high dose of aspirin is not recommended.


Sometimes, one drug can make another drug less effective, or the group can increase the risk to the patient. This is called pharmacological reaction. The most common medications with which aspirn may interact are:

  1. Anti-inflammatory pain relievers, Such as diclofenac, ibuprofen, indomethacin, and naproxen. This can increase the risk of stomach bleeding if taken with aspirn.
  2. Methotrexate is used in the treatment of cancer and certain autoimmune diseases. Aspirin can make it difficult for the body to get rid of methotrexate, leading to dangerously high levels of methotrexate in the body.
  3. Selective serotonin reuptake inhibitors (SSRI) for antidepressants, such as citalopram, fluoxetine, paroxetine, venlafaxine, and sertraline. Taking it with aspirn, can increase the risk of bleeding.
  4. Warfarin, an anticoagulant drug, or blood thinner, prevents blood from clotting. If aspirn is taken with warfarin, it can reduce the effects of the anticoagulant drug and increase the risk of bleeding. However, in some cases, your doctor may prescribe aspirn with warfarin.

These are not the only drugs that cannot be used with aspirn. Anyone taking aspirn should inform their doctor, as other medications can also interact.

Side effects

The most common side effects  are:

  1. Irritation of the stomach or intestines
  2. Indigestion
  3. Nausea

The following adverse effects are possible, but less common:

  1. Exacerbation of asthma symptoms
  2. Vomiting
  3. Gastritis
  4. Bleeding stomach
  5. Bruises
  6. A rare side effect of low-dose is hemorrhagic stroke.

Aspirin can help prevent and treat a range of conditions, but anyone taking aspirn should speak to his doctor first. Anyone under the age of 16 should not usually take aspirn, except in rare cases and under medical supervision.