Aspirin for headaches: What you need to know

Aspirin has been around for more than 100 years.

It may be found in nearly every medicine cabinet in America and has a variety of uses. People take aspirin to reduce fever, relieve pain and muscle aches and lower inflammation. And when a headache strikes, aspirin is the medicine that many turn to for relief. There’s good reason for this — aspirin has been shown to be an effective and safe headache reliever for most people. However, it isn’t suitable for everyone or for every type of headache.

Aspirin can help reduce symptoms of headaches. Aspirin’s main ingredient is acetylsalicylic acid. It is classified as a nonsteroidal anti-inflammatory drug (NSAID), which means it's not a steroid (like prednisone) but works to fight inflammation, such as that seen in arthritis and muscle sprains. Because of this, aspirin is a very effective pain reliever, including for pain caused by some, but not all, types of headaches.

Aspirin has proven to be effective in treating migraines in some people. In a review of multiple studies, researchers found that high-dose aspirin (900–1,300 mg) taken at the onset of a migraine headache is a safe and effective treatment. This dose was significantly more effective than a placebo and comparable to 400 mg of ibuprofen (Motrin, Advil) and 50 mg of sumatriptan (Imitrex), a potent and commonly used prescription migraine medicine. Aspirin also has fewer side effects than some prescription migraine drugs. In addition, these same researchers found that lower doses of daily aspirin (81–325 mg) may be an effective and safe treatment option for the prevention of migraines.

Some people take aspirin for what they believe are high blood pressure headaches, although evidence suggests that high blood pressure does not routinely cause headaches in most cases.

However, if you have high blood pressure and you get a headache, aspirin is one of the safer drugs to use to relieve the pain. All NSAIDs can raise blood pressure slightly, but aspirin's effect is very small. Acetaminophen, or Tylenol, also is a safer choice because it is not an NSAID. If you have high blood pressure, check with your doctor to see which pain reliever is best for you. However, if you have uncontrolled high blood pressure, do not take aspirin. Uncontrolled high blood pressure puts you at risk for a hemorrhagic stroke, which is worsened by aspirin.

Aspirin can be taken for tension headaches, but it may provide only mild relief for this type of headache. An analysis of multiple studies showed that a single dose of aspirin between 500–1,000 mg provided some benefit to adults who suffered from frequent tension-type headaches. These adults used less "rescue medication" (additional painkillers, two hours after taking the aspirin) and reported higher satisfaction with treatment than those adults who used a placebo. But the researchers noted that the amount and quality of the evidence was limited.

Aspirin or other pain relievers are sometimes combined with caffeine or other medicines for better pain relief for tension headaches.

Evidence suggests that aspirin and other over-the-counter pain relievers don't usually relieve the pain from cluster headaches.

There are several reasons to use caution when considering aspirin for a headache. These reasons are related to various health conditions:

• Children and teens under the age of 19 should not take aspirin for any reason (unless specifically instructed to by a physician) due to the association in this age group between aspirin and Reye’s syndrome, a potentially fatal illness that causes brain swelling and liver damage.
• People who are allergic or sensitive to NSAIDs should avoid aspirin.
• Those with bleeding ulcers should not take aspirin. Aspirin can cause stomach upset in many cases and bleeding ulcers in the worst cases.
• Those with liver or kidney disease should not take aspirin unless they do so with advice from a healthcare provider.
• People who consume three or more alcoholic drinks per day should not take aspirin unless instructed to do so by a healthcare provider.
• Those who have uncontrolled high blood pressure should not take aspirin unless advised otherwise by a healthcare provider.
• Those who are already on a blood thinner should not take aspirin unless specifically instructed to by a healthcare provider.
• Anyone with a bleeding disorder, such as hemophilia, should not take aspirin unless advised to do so by a healthcare provider.
• Pregnant women should not take aspirin unless advised to do so by their physician.

Aspirin can treat many types of headaches, but there are some people who should refrain from taking it. As with any medication, talk to your doctor before taking aspirin.

Published January 2023.