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Low-Dose Aspirin Side Effects: What to Know

Last reviewed: December 2025

Overview

Even at low doses, aspirin carries significant risks, primarily related to bleeding. The decision to use low-dose aspirin involves weighing cardiovascular benefits against bleeding risks. Understanding these side effects is crucial for anyone taking daily aspirin.

Common Side Effects

Gastrointestinal:

  • Stomach upset or indigestion
  • Nausea
  • Heartburn
  • Mild stomach pain

Other common effects:

  • Easy bruising
  • Prolonged bleeding from minor cuts
  • Bleeding gums when brushing teeth

These effects occur because aspirin affects platelets throughout the body, not just in the heart.

Serious Side Effects

Gastrointestinal Bleeding

This is the most significant risk:

  • Upper GI bleeding — from stomach or duodenum
  • Can occur without warning symptoms
  • Risk increases with: age, history of ulcers, H. pylori infection, other NSAIDs
  • Symptoms: black/tarry stools, vomiting blood, severe stomach pain

Enteric coating note: Contrary to popular belief, enteric-coated aspirin does NOT significantly reduce GI bleeding risk. The bleeding occurs systemically due to aspirin’s antiplatelet effects, not just from local irritation.

Hemorrhagic Stroke

  • Aspirin can increase risk of bleeding in the brain
  • This is why benefit-risk assessment is critical
  • More concerning in people with uncontrolled high blood pressure

Other Serious Bleeding

  • Post-surgical bleeding
  • Bleeding from injuries
  • Internal bleeding

Who Is at Higher Risk

Factors that increase bleeding risk:

  • Age over 70
  • History of GI bleeding or ulcers
  • Use of other blood thinners (warfarin, DOACs)
  • Use of other NSAIDs
  • Use of corticosteroids
  • Heavy alcohol use
  • Uncontrolled high blood pressure
  • History of hemorrhagic stroke
  • Kidney or liver disease

Aspirin Sensitivity and Allergy

Aspirin-exacerbated respiratory disease (AERD):

  • Triad of asthma, nasal polyps, and aspirin sensitivity
  • Can cause severe asthma attacks
  • Affects about 7% of adults with asthma

True aspirin allergy:

  • Rare but serious
  • Hives, swelling, anaphylaxis
  • Requires complete avoidance

Rebound Effect

Important consideration:

  • Stopping low-dose aspirin suddenly can temporarily increase cardiovascular risk
  • “Rebound” platelet activity may occur
  • Always discuss stopping with a healthcare provider
  • May need to time discontinuation around surgeries

Long-Term Considerations

With chronic use:

  • Cumulative bleeding risk
  • Potential kidney effects (rare at low doses)
  • May mask symptoms of other conditions

When to Seek Medical Attention

Get immediate help for:

  • Black, tarry stools
  • Vomiting blood or material that looks like coffee grounds
  • Severe stomach pain
  • Signs of stroke (even if taking aspirin for prevention)
  • Severe bleeding that won’t stop
  • Signs of allergic reaction

Reducing Side Effects

Strategies that may help:

  • Take with food
  • Avoid alcohol
  • Avoid other NSAIDs when possible
  • Treat H. pylori if present
  • Some people take a PPI (proton pump inhibitor) for GI protection

Sources

  • FDA — Aspirin Safety Information
  • American Heart Association — Aspirin Benefits and Risks
  • USPSTF — Aspirin for Primary Prevention of CVD
  • Gastroenterology — GI Bleeding Risk with Aspirin
Last reviewed: December 2025