Why does Excedrin smell like vinegar? (+1 reasons)

In this article, we will discuss the ingredients in Excedrin that give off a vinegar-like smell due to improper storage conditions. We will also discuss alternative therapies which can be used instead of Excedrin for migraine attacks.

Why does Excedrin smell like vinegar?

Excedrin smells like vinegar due to the degradation of aspirin. Aspirin present in Excedrin is acetylsalicylic acid. Due to its degradation, it releases acetic acid that gives a peculiar vinegar-like smell. You should not consume Excedrin if it gives a bad odour (1).

Excedrin may give a vinegar-like smell if it is not stored in adequate storage conditions. Due to temperature abuse and humidity aspirin will begin to degrade. Therefore, you must store Excedrin in a tightly closed container at room temperature.

Excedrin also contains caffeine and paracetamol, however, no literature reports their degradation product to smell like vinegar. Although it will not produce any toxicity, the guidelines suggest that you should discard Excedrin immediately.

Does a vinegar-like smell affect the effectiveness of Excedrin?

The effectiveness of Excedin decreases when it begins to give a vinegar-like odour. However, toxicity is not reported. As aspirin converts to acetic acid outside the body, it loses its effectiveness and may not provide symptomatic pain treatment.

Although two other ingredients, caffeine and paracetamol, are also present in Excedrin, it would not be possible for a patient to take foul-smelling medication. The manufacturer of Excedrin and the Food and Drug Administration (FDA) also guides us to discard Excedrin (2).

What does research suggest?

According to a study conducted to evaluate the thermal decomposition of aspirin to salicylic acid and acetic acid, the researchers found a directly proportional relation between temperature and salicylic acid concentration.

This means that as the temperature increased, the rate of conversion of aspirin to salicylic acid and acetic acid also increased. The experiment was conducted at different temperatures including 30°C, 45°C, 60°C, 75°C, and 90°C (3).

What are the correct storage conditions for Excedrin?

To reduce the chances of aspirin degradation to acetic acid, you should follow the manufacturer’s guidelines for proper storage of Excedrin.

  • Store Excedrin at room temperature (20-25°C) and relative humidity.
  • Store Excedrin at a location where the container will not be exposed to excessive heat and moisture.
  • Close the container appropriately. Do not leave the cap open.
  • Keep Excedrin out of the reach of children and pets.
  • Do not use Excedrin past its expiry date.

What are the alternatives to Excedrin if it smells like vinegar?

If you perceive that Excedrin is giving a vinegar-like smell then you should stop taking Excedrin immediately. Aspirin is one of the active ingredients of Excedrin and has a pharmacological effect. However, acetic acid has no such use.

After consulting your doctor, you may opt for other treatment strategies. Excedrin is an over-the-counter medication, often prescribed for migraine attacks. You may use the following medicines instead of Excedrin after consulting your doctor:


Excedrin contains acetaminophen along with aspirin and caffeine. You may take acetaminophen (1000 mg) alone to get relief from the pain. However, acute ingestion of more than 150 mg/kg or 12 grams of acetaminophen increases the occurrence of hepatotoxicity (4).


Ibuprofen (400 mg), a nonsteroidal anti-inflammatory drug (NSAID), may be taken instead of Excedrin. However, you should never take Excedrin and ibuprofen together as it may cause gastrointestinal complications.


It is safe to give sumatriptan (50 mg) intravenously, subcutaneously, or orally for the treatment of migraine and associated headaches. Sumatriptan proves more effective if it is administered immediately after the onset of a migraine attack (5).

As a pharmacist, I always advise my patients to store their medications under appropriate storage conditions. Additionally, you should avoid using Excedrin past its expiry date or shelf-life.

Excedrin gives off a vinegar-like smell, however, you may not notice such degradations for other drugs. Therefore, it is always safe to discard your medicines appropriately, rather than use drugs that have no beneficial effect.

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Marsella G. Aspirin. ChemMatters, February. 1993. https://www.teachnlearnchem.com/chemmatters-feb1993-aspirin-marsella.pdf


Karch AM. Waste not?. AJN The American Journal of Nursing. 2008 Jul 1;108(7):86-7. https://journals.lww.com/ajnonline/Fulltext/2008/07000/Waste_Not_.37.aspx


Karimirad R. Exploring the Effect of Temperature on the Concentration of Salicylic Acid in Acetylsalicylic Acid. https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/653b3f3348dad2312073e584/original/exploring-the-effect-of-temperature-on-the-concentration-of-salicylic-acid-in-acetylsalicylic-acid.pdf


Agrawal S, Khazaeni B. Acetaminophen toxicity. https://www.ncbi.nlm.nih.gov/books/NBK441917/


Brar Y, Hosseini SA, Saadabadi A. Sumatriptan. InStatPearls [Internet] 2023 Nov 12. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK470206