Common Side Effects of Aspirin
Aspirin, used for pain relief, fever reduction, and heart protection, often causes stomach upset, heartburn, or nausea, especially at higher doses. These occur because aspirin irritates the stomach lining.[1]
Serious Risks and When to Worry
Heavy or long-term use raises bleeding risks, including gastrointestinal bleeding, ulcers, or brain hemorrhage—particularly in those over 60 or on blood thinners. Allergic reactions like hives, swelling, or asthma attacks affect about 1% of users, more common in people with nasal polyps or asthma.[1][2] Rare but severe effects include kidney damage or Reye's syndrome in children with viral infections.
Who Faces Higher Risks?
- Older adults: Increased ulcer and bleed odds.
- Children/teens: Avoid during flu or chickenpox due to Reye's risk.
- Pregnant people: Third-trimester use links to birth complications; consult a doctor.[2]
Daily low-dose (81mg) for heart health cuts some risks but doesn't eliminate them.
How Does Dosage Affect Side Effects?
Low doses (under 325mg) for heart prevention cause fewer issues than high doses for pain. Enteric-coated versions may reduce stomach irritation but not bleeding risk.[1]
Drug Interactions to Watch
Aspirin amplifies bleeding with NSAIDs (ibuprofen), warfarin, or alcohol. It can weaken effects of some blood pressure meds.[2]
What Patients Report Most
Online forums and FDA data highlight stomach pain (most common), easy bruising, and tinnitus (ringing ears) at high doses. Long-term users note fatigue or anemia from slow bleeds.3
[1]: https://www.fda.gov/drugs/postmarket-drug-safety-information-patients-and-providers/aspirin-reducing-your-risk-heart-attack-and-stroke-understanding-risks-and-benefits
[2]: https://www.mayoclinic.org/drugs-supplements/aspirin-side-effects/art-20385509