Can Aspirin Cause Fever as a Side Effect? How to Cope

Aspirin does not commonly cause fever on its own, but fever can occur in specific situations such as aspirin overdose, certain allergic or hypersensitivity reactions, and the rare condition called Reye’s syndrome in children and teenagers. ^[1] In adults, fever linked to aspirin more often suggests overdose or another underlying issue rather than a routine side effect. ^[2]

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When Fever Can Be Related to Aspirin

• Overdose (acute or chronic): Fever can be one of the symptoms of taking too much aspirin, either at once or building up over time. Other signs may include vomiting, rapid breathing, confusion, or decreased urination. ^[1] In severe cases, very high fevers can occur and are medical emergencies. ^[3] Overdose can happen unintentionally, for example, by combining multiple products containing aspirin. ^[2]

• Allergic or hypersensitivity reactions: Aspirin can cause allergic reactions which may include hives, facial swelling, wheezing, and shock; drug allergies can sometimes present with fever along with rash and other symptoms. ^[4] [PM18] If fever occurs with rash, swelling, or breathing trouble after aspirin, this may indicate an allergic reaction. ^[4] [PM18]

• Reye’s syndrome (children/teens): Children and teenagers recovering from flu or chickenpox should not take aspirin because of the risk of Reye’s syndrome, which can begin with behavior changes, nausea, and vomiting and may be serious. ^[5] Because of this risk, aspirin should be avoided in children and teenagers for viral illnesses. ^[6]

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What Aspirin Usually Does for Fever

Aspirin is an antipyretic (fever-reducing) medicine and can lower temperature in adults, typically within 1–2 hours. ^[6] However, if a fever does not improve after taking a proper dose, or lasts more than about three days, you should contact a healthcare provider. ^{[7] [6]}

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How to Cope if You Suspect Aspirin-Related Fever

Step-by-step actions

• Stop aspirin and check other products: If you develop fever soon after aspirin use especially with other concerning symptoms pause aspirin and review all medicines to ensure you are not taking multiple products with aspirin. ^[2] Consider whether any cold/flu remedies or combination products also contain aspirin. ^[2]

• Assess for emergency symptoms: Seek urgent care if there is severe or persistent fever, confusion, severe vomiting, rapid breathing, seizures, or signs of allergic reaction like facial swelling or wheezing. ^{[3] [1]} These can signal overdose or serious reaction requiring immediate treatment. ^{[3] [1]}

• Use alternatives for fever reduction (adults): If you need fever relief, acetaminophen or ibuprofen are reasonable options when used as directed. ^[6] Avoid combining multiple acetaminophen products to prevent overdose. ^[8]

• Children and teens: Do not give aspirin for fever unless a clinician specifically advises it, because of Reye’s syndrome risk; use acetaminophen or ibuprofen per age-appropriate dosing if advised. ^{[6] [9]}

• Monitor duration and severity: If fever persists above 102–103°F (38.9–39.4°C), doesn’t respond to medicine, or lasts beyond 1–3 days, contact a clinician. ^{[8] [6]} Persistent or worsening fever may indicate a condition needing medical evaluation. ^[6]

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When to Seek Medical Help

• Immediate help: High fever with confusion, rapid breathing, seizures, or collapse; symptoms of allergic reaction (hives, facial swelling, wheezing, shock); suspected large dose ingested. ^{[3] [4]} Call emergency services or poison control for suspected overdose. ^[1]

• Prompt evaluation: Fever that does not improve after proper dosing, lasts more than three days in adults, or any fever in a child given aspirin. ^{[7] [6]} Behavior changes with nausea/vomiting in children or teens taking aspirin require urgent medical consultation due to Reye’s syndrome risk. ^[5]

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Practical Safety Tips

• Check labels carefully: Many cold and pain products contain aspirin; avoid doubling up unintentionally. ^[2]
• Use age-appropriate medicines: Adults can use aspirin for fever, but children and teenagers should avoid it for viral illnesses. ^[6]
• Dose correctly: Follow package instructions; do not exceed recommended dose or duration. ^[7]
• Know warning signs: Rash, swelling, wheezing, or persistent fever after aspirin need medical review. ^[4]
• Consider safer alternatives: Acetaminophen or ibuprofen are commonly used options for fever control when aspirin is not appropriate. ^{[8] [6]}

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Bottom Line

Aspirin rarely causes fever as a straightforward side effect, but fever can occur with overdose, allergic reactions, or in the context of Reye’s syndrome in young people. ^{[1] [5]} If fever appears after taking aspirin especially with other warning symptoms stop the drug, use appropriate alternatives, and seek medical advice. ^{[3] [6]}