Aspirin and Diarrhea: Causes, Risks, and Practical Coping Tips

Yes, aspirin can cause diarrhea in some people, although it does not happen to everyone. ^[1] Aspirin’s gastrointestinal side effects range from mild issues like upset stomach to more serious problems such as ulcers and bleeding. [PM17] Diarrhea is listed among adverse effects that may require medical attention depending on severity and associated symptoms. ^[2]

How Aspirin Can Lead to Diarrhea

Aspirin (acetylsalicylic acid) can irritate the gastrointestinal lining and alter protective prostaglandins, which may trigger diarrhea in susceptible individuals. [PM16] Even low-dose (81 mg) enteric‑coated forms list diarrhea among possible side effects, indicating that coating does not completely prevent GI reactions. ^[3] Risks increase when combined with other NSAIDs or in people with prior ulcers or older age. [PM16] In combination products (aspirin with extended‑release dipyridamole), diarrhea occurs in a notable proportion of users in clinical data. ^[4]

When to Seek Medical Care

Contact a clinician urgently if diarrhea occurs with warning signs of stomach bleeding, such as black or tarry stools, or abdominal pain and cramping. ^[2] Stop aspirin and seek medical help if you develop signs of bleeding or an allergic reaction. ^[3] Severe or persistent diarrhea, dehydration, fainting, or blood in the stool warrants prompt evaluation. ^[1]

Practical Coping Steps

Consider taking aspirin with food and adequate fluids to reduce stomach irritation. [PM17] Discuss dose: lowering daily dose (often below 350 mg) can lessen GI adverse effects while maintaining intended benefits, if appropriate for your condition. [PM15] Ask about gastroprotection (proton pump inhibitors) if you need ongoing aspirin and have GI risk factors, as PPIs can reduce ulcer risk and are generally better tolerated than misoprostol, which itself can cause diarrhea. [PM17] If diarrhea is mild and not accompanied by alarm features, oral rehydration solutions are preferred to sports drinks to replace fluid and electrolytes properly. ^[5]

Medication Considerations

Enteric‑coated aspirin may be gentler for the stomach in some people, but diarrhea can still occur with these formulations. ^[3] If aspirin is necessary for heart protection, clinicians often weigh cardiovascular benefits against GI risks and may add a PPI to lower ulcer and bleeding risk. [PM17] Combination therapy with dipyridamole is associated with diarrhea more often than aspirin alone, so reporting symptoms allows adjustment of therapy. ^[4]

Red Flags You Shouldn’t Ignore

• Black, tarry stool or vomiting blood can indicate bleeding and needs urgent care. ^[2]
• Severe abdominal pain, cramping, or burning may signal significant GI injury. ^[2]
• Persistent weakness, fainting, or signs of dehydration require medical assessment. ^[1]

Summary

Aspirin can cause diarrhea as a recognized gastrointestinal side effect, ranging from mild to significant depending on individual risk factors and dose. ^[1] Managing it typically involves dose review, taking with food, hydration using proper oral rehydration solutions, and considering protective medications like PPIs when aspirin must be continued. [PM17] Seek medical care promptly if diarrhea is severe or accompanied by signs of bleeding or intense abdominal pain. ^[2]