Aspirin Side Effects: What You Need to Know Before Taking It

When you reach for aspirin, a common over-the-counter pain reliever and blood thinner used for headaches, fever, and heart attack prevention. Also known as acetylsalicylic acid, it’s one of the most widely used drugs in the world—but that doesn’t mean it’s safe for everyone. Many people think aspirin is harmless because it’s cheap and available without a prescription. But it’s a powerful drug with real dangers, especially when taken daily or mixed with other medicines.

One of the biggest risks is stomach bleeding, a serious side effect caused by aspirin’s effect on the protective lining of the stomach and intestines. Even low-dose aspirin, often taken for heart protection, can cause ulcers or internal bleeding. Older adults, people with a history of ulcers, or those who drink alcohol regularly are at higher risk. You might not notice symptoms until it’s serious—dark stools, vomiting blood, or sudden weakness could be warning signs.

Another hidden danger is Reye’s syndrome, a rare but life-threatening condition linked to aspirin use in children and teens with viral infections like the flu or chickenpox. This is why aspirin is never recommended for anyone under 18 unless a doctor specifically says so. The same goes for aspirin interactions, how it reacts dangerously with blood thinners, NSAIDs like ibuprofen, or even some herbal supplements like ginkgo or garlic. Mixing these can increase bleeding risk or cancel out aspirin’s benefits.

Some side effects are less scary but still annoying—like ringing in the ears, dizziness, or nausea. These often show up when people take too much. If you hear a constant buzz in your ears after taking aspirin, that’s your body telling you to cut back. It’s not just a nuisance; it can be an early sign of toxicity.

And don’t forget: aspirin doesn’t work the same for everyone. Some people are resistant to its blood-thinning effects, meaning it won’t protect their heart like it should. Others are so sensitive they get reactions just from a single pill. If you’ve ever had a rash, swelling, or trouble breathing after taking aspirin, you could have a true allergy—and you need to avoid it completely.

What you’ll find below are real, practical guides from people who’ve dealt with these issues firsthand. From parents wondering if aspirin is safe for their child’s fever, to older adults trying to balance heart health with stomach safety, these posts don’t just list side effects—they show you how to recognize them, avoid them, and talk to your doctor about safer options.