Does Diclofenac Cause Diarrhea? Causes, Management, and Alternatives

October 8, 2025 •

3 min read

Research shows that digestive issues, including diarrhea, are among the most commonly reported side effects of oral diclofenac. As a nonsteroidal anti-inflammatory drug (NSAID), diclofenac is widely prescribed for pain and inflammation, but its impact on the gastrointestinal (GI) tract is a well-known concern that can range from uncomfortable to serious.

Quick Summary

Diclofenac can cause gastrointestinal side effects like diarrhea by disrupting protective stomach lining and altering gut bacteria. Management involves hydration and dietary changes, but severe symptoms warrant medical care.

Key Points

Diarrhea is a Common Side Effect: Diclofenac frequently causes gastrointestinal issues, including diarrhea, especially with oral administration.
Mechanism Involves Prostaglandin Inhibition: The drug blocks protective prostaglandins in the gut lining, leading to increased vulnerability and inflammation.
Gut Microbiome Disruption Plays a Role: NSAID use can cause an imbalance in gut bacteria, contributing to digestive issues like diarrhea.
Manage Mild Symptoms with Hydration and Diet: Staying hydrated, eating bland foods, and taking the medication with a meal can help alleviate mild diarrhea.
Recognize Warning Signs of Serious Complications: Black, tarry stools, or persistent severe abdominal pain could indicate internal bleeding, a serious risk associated with NSAIDs.
Consider Alternative Medications: Options like acetaminophen, COX-2 inhibitors, or topical diclofenac can be used for pain relief with a lower risk of GI side effects.

Understanding the Link Between Diclofenac and Your Gut

Diclofenac is a nonsteroidal anti-inflammatory drug (NSAID) that works by inhibiting the body's production of prostaglandins. While effective for pain and inflammation, this mechanism of action also interferes with the prostaglandins that protect the lining of your stomach and intestines. The subsequent damage to the mucosal lining can lead to various gastrointestinal (GI) side effects, with diarrhea being one of the most frequently reported.

The Pathophysiology of NSAID-Induced Diarrhea

The development of diarrhea and other GI issues is more complex than simple irritation. NSAIDs can damage the epithelium of the small bowel, causing increased intestinal permeability, often referred to as 'leaky gut'. This allows bacteria and other toxins to pass through the intestinal wall, triggering an inflammatory response that can manifest as diarrhea. Additionally, some research suggests that NSAIDs can disrupt the delicate balance of the gut microbiome, a condition known as dysbiosis. This imbalance of gut bacteria can also contribute to digestive distress and irregular bowel movements.

Managing Diarrhea Caused by Diclofenac

If you experience mild diarrhea while taking diclofenac, several home management strategies can provide relief. However, always consult a healthcare provider before starting or stopping any medication.

Stay Hydrated: Diarrhea can lead to dehydration. Drinking plenty of water and other clear fluids is crucial.
Modify Your Diet: Eating bland, easy-to-digest foods (like the BRAT diet: bananas, rice, applesauce, toast) can be helpful. Avoid fried, greasy, or spicy foods that can further irritate your digestive system.
Take Diclofenac with Food: Taking your medication with a meal can help reduce general stomach upset.
Avoid Alcohol: Combining diclofenac with alcohol can increase the risk of GI side effects and should be avoided.
Consider Over-the-Counter Remedies: In some cases, over-the-counter medications like loperamide (Imodium) or bismuth subsalicylate (Pepto-Bismol) may be used, but only with a doctor's approval.

When to Seek Medical Attention

While mild diarrhea may resolve on its own as your body adjusts, more severe or persistent symptoms can be a sign of a serious complication. Diclofenac carries a black box warning from the FDA for serious gastrointestinal adverse events, including bleeding, ulceration, and perforation of the stomach or intestines. You should stop taking diclofenac and call your doctor immediately if you experience any of the following:

Black, tarry, or bloody stools
Vomiting blood or material that looks like coffee grounds
Severe abdominal pain or stomach cramps
Unexplained weight loss or fatigue
Yellowing of the skin or eyes (jaundice), dark urine, or liver-related symptoms

Diclofenac vs. Other Pain Relievers

For those who experience diarrhea or other significant GI side effects from diclofenac, healthcare providers may recommend an alternative. The table below compares diclofenac to other common pain relievers based on their potential for gastrointestinal side effects.


Medication Type	Examples	GI Side Effect Risk	Notes
Non-Selective NSAIDs	Diclofenac, Ibuprofen, Naproxen	High	Block both COX-1 and COX-2 enzymes, leading to reduced prostaglandin protection in the GI tract.
COX-2 Selective Inhibitors	Celecoxib (Celebrex)	Lower	Primarily block the COX-2 enzyme, potentially causing fewer GI side effects than traditional NSAIDs, but have their own risks, including cardiovascular.
Non-NSAID Pain Relievers	Acetaminophen (Tylenol)	Lower	Provides pain relief and fever reduction but does not have anti-inflammatory properties. Causes fewer GI issues but has liver-related risks at high doses or with heavy alcohol use.
Topical NSAIDs	Diclofenac topical gel (Voltaren)	Lower	Applied directly to the skin, resulting in less systemic absorption and a lower risk of GI side effects compared to oral formulations.

Conclusion: Making Informed Choices for Digestive Health

Does diclofenac cause diarrhea? Yes, it is a recognized and relatively common side effect due to the drug's impact on the gastrointestinal lining and gut microbiome. While mild cases can often be managed with simple dietary and hydration adjustments, it is vital to recognize the signs of more serious complications, like GI bleeding, and seek prompt medical care. If diclofenac causes significant digestive distress, several alternative pain management strategies are available, including different classes of pain relievers and topical formulations. The best course of action is to discuss your symptoms and concerns with a healthcare professional to find the safest and most effective treatment for your individual needs. For more comprehensive information on diclofenac and other medications, the National Institutes of Health (NIH) is an excellent resource.

Frequently Asked Questions

Yes, diarrhea is a common gastrointestinal side effect reported by many people taking oral diclofenac. Other related symptoms include stomach pain, nausea, and indigestion.

Diclofenac, like other NSAIDs, inhibits prostaglandins that protect the stomach and intestinal lining. This can damage the GI tract, increase intestinal permeability, and alter the gut microbiome, all of which can lead to diarrhea.

Taking your medication with a meal can reduce stomach upset. You should also stay well-hydrated and avoid alcohol, which can worsen digestive side effects.

While mild diarrhea may be temporary, you should seek immediate medical attention if you experience bloody or black stools, vomiting that resembles coffee grounds, or severe stomach pain. These could be signs of serious internal bleeding.

Alternatives include acetaminophen (Tylenol), which has fewer GI side effects but lacks anti-inflammatory properties, and COX-2 selective inhibitors like celecoxib, which are associated with a lower GI risk. Topical diclofenac gel also carries a lower risk.

Diarrhea is less common with topical diclofenac (applied to the skin) compared to oral forms. The lower systemic absorption reduces the risk of gastrointestinal side effects, though some risk still exists.

Both are non-selective NSAIDs with a risk of GI side effects. Some studies suggest diclofenac may carry a higher risk of serious GI bleeding compared to ibuprofen, but risks can vary by dose and individual.