Enteric-Coated Aspirin vs. Plain Aspirin: What’s the Difference?

A recent study found that enteric-coated aspirin is just as effective as uncoated aspirin, but not necessarily any safer. The findings confirm that both types of aspirin can treat and prevent cardiovascular events, like a heart attack or stroke.

The study looked at data from 10,678 participants who had been diagnosed with atherosclerotic cardiovascular disease. About 69% reported taking enteric-coated aspirin, and 31% reported taking uncoated aspirin.

The researchers found no significant difference in effectiveness or safety between the groups, which suggested that coated aspirin does not provide a protective advantage over regular aspirin.

If both types of aspirin are safe and effective, does it matter which one you keep in your medicine cabinet? Here’s what experts say about the differences between enteric-coated and plain aspirin and when you might want to choose one over the other.

Enteric-Coated vs. Non-Coated Aspirin

Aspirin has been one of the most important drugs in our arsenal for over a hundred years, but many people don’t know there are two kinds: enteric-coated and non-coated aspirin. Most aspirin sold in the United States is enteric-coated (also called safety-coated), but there is also uncoated (“regular” or “plain”) aspirin available.

Even if they’re both safe and effective, plain aspirin and coated aspirin still have some key differences.

Where It’s Absorbed

The main difference between coated and non-coated aspirin is where it gets absorbed, David Maron, MD, professor of medicine at Stanford Prevention Research Center, told Verywell.

Non-coated aspirin gets broken down and absorbed in the stomach. The coating on enteric-coated aspirin protects it from stomach acid, so it can pass into the small intestine and be absorbed there.

People who frequently take large doses of aspirin are at a higher risk for stomach ulcers, lesions, gastrointestinal bleeding, and even death. Since coated aspirin is absorbed in the small intestine, you’d think it would be less harsh on the stomach. Maron said that’s a common misconception.

While enteric-coated aspirin has “been recommended in preference to plain uncoated aspirin to reduce bleeding,” there’s no study that proves “coated aspirin is safer than uncoated aspirin,” he said.

In fact, a 2020 systematic review study found no evidence that enteric-coated aspirin protects against stomach damage and showed it could even lead to small bowel damage.

Blood Clotting Prevention

Aspirin also inhibits the formation of platelets in the blood, so many people at risk for heart disease take daily low-dose aspirin to help prevent blood clots. Since enteric-coating aspirin has to wait until it gets to the small intestines to be absorbed into the bloodstream, its effects can take longer than regular aspirin, which is quickly absorbed in the stomach.

Mark Effron, MD, an author on the new study and a cardiologist at the John Ochsner Heart and Vascular Institute at the University of Queensland-Ochsner Clinical School, told Verywell that his team’s findings showed coated aspirin was not associated with changes in effectiveness for the secondary prevention of a heart attack or stroke.

However, older research has suggested that enteric-coated aspirin is less effective at preventing blood clot formation in healthy people, perhaps because the release of the drug is delayed since it’s not broken down in the stomach.

Aspirin and Heart Health

While aspirin was originally developed to reduce pain and fever, it is now widely used to help prevent heart attacks and strokes. Aspirin is also used as an emergency treatment when someone is having a heart attack.

Maron said that current guidelines “do not recommend coated over uncoated aspirin for patients with coronary artery disease.”

Some providers recommend that patients who are at high risk of heart disease take a low daily dose of either coated or non-coated aspirin to help prevent arterial blood clots. However, when taking an aspirin (either an 81 mg or 325 mg dose) during a heart attack, Maron recommends taking a non-enteric-coated, chewable aspirin.

Coated aspirin should not be chewed or crushed. However, if you only have enteric-coated aspirin on hand in an emergency, providers suggest chewing it so it can break down and get absorbed faster.

Who Should—and Shouldn’t—Take Aspirin

Taking aspirin has benefits and risks, so you should talk to your provider about whether you need to take a low dose daily. In 2022, the U.S. Preventive Services Task Force (USPSTF) updated aspirin guidelines to remove the recommendation of daily aspirin for the prevention of heart disease in people over the age of 60. However, the FDA and USPSTF still recommend daily aspirin for secondary prevention of recurrent heart attacks or strokes.

Since aspirin can increase bleeding and damage the GI tract, some people should not take aspirin unless specifically told to do so by their provider.

Aspirin may not be safe for:

• People with a low risk of heart attack
• People with an aspirin allergy
• People aged 60 and older (who have a higher risk of bleeding)
• People who have a bleeding or clotting disorder
• People who have a history of stomach ulcers or gastrointestinal bleeding
• People having medical or dental procedures that lead to bleeding
• People who regularly drink alcohol