Can Voltaren Gel Cause Diarrhea? A Review of GI Side Effects

October 9, 2025 •

3 min read

While only about 6% of the active ingredient in Voltaren gel is absorbed systemically, compared to oral diclofenac, it can still lead to systemic side effects. The question many users have is: can Voltaren gel cause diarrhea and other gastrointestinal problems?

Quick Summary

An examination of whether the topical NSAID Voltaren (diclofenac) gel can lead to diarrhea and other gastrointestinal side effects due to systemic absorption.

Key Points

Diarrhea is a possible side effect: Yes, Voltaren gel can cause diarrhea and other gastrointestinal issues like stomach pain, gas, and nausea due to systemic absorption of its active ingredient, diclofenac.
Lower Risk Than Oral NSAIDs: The risk of GI side effects, including diarrhea, is significantly lower with topical Voltaren gel compared to oral diclofenac tablets because less medication enters the bloodstream.
Systemic Absorption is the Cause: Though applied to the skin, a small amount (about 6%) of diclofenac is absorbed systemically, which can lead to body-wide side effects.
Black Box Warning: Like all NSAIDs, Voltaren gel has an FDA black box warning for serious GI risks, including bleeding, ulcers, and perforation, which can occur without warning.
Risk Factors Increase Danger: Individuals who are older, have a history of ulcers, take other NSAIDs or blood thinners, or drink alcohol are at a higher risk for GI complications.
Monitor for Severe Symptoms: While mild diarrhea may occur, severe or persistent diarrhea, bloody stools, or intense stomach pain requires immediate medical attention.
Use as Directed: To minimize risk, always use the lowest effective dose for the shortest duration possible and do not apply to more than two body areas at once.

Understanding Voltaren Gel and Its Mechanism

Voltaren Arthritis Pain Gel, containing diclofenac sodium, is a topical NSAID used to relieve osteoarthritis joint pain. Unlike oral NSAIDs, the gel is applied directly to the skin, allowing the medication to target inflammation locally. While this reduces overall systemic absorption compared to oral forms, some diclofenac does enter the bloodstream. This systemic presence is why side effects affecting the whole body, including the gut, are possible.

The Link: Can Voltaren Gel Cause Diarrhea?

Yes, Voltaren gel can cause diarrhea. The diclofenac absorbed into the bloodstream can impact the gastrointestinal (GI) tract. NSAIDs like diclofenac inhibit COX enzymes, which are necessary for maintaining the protective lining of the stomach and intestines. This can lead to GI issues. Reducing protective prostaglandins in the gut makes the lining more vulnerable, potentially causing symptoms such as diarrhea, stomach pain, and gas.

Diarrhea is listed as a potential side effect for Voltaren gel and similar topical diclofenac products. Though less common than with oral diclofenac, it can still occur. Mild instances may resolve on their own, but severe or persistent diarrhea warrants medical consultation to rule out serious GI or liver complications.

Other Potential Gastrointestinal Side Effects

Systemic absorption of diclofenac from Voltaren gel can also cause other GI problems:

Common Side Effects: Nausea, heartburn, stomach pain, gas, bloating, and constipation are possible.
Serious Side Effects: All NSAIDs, including Voltaren gel, have an FDA black box warning for increased risk of severe GI events like bleeding, ulcers, and perforation, which can be life-threatening. These can occur without obvious symptoms. Watch for signs such as bloody or black stools, vomiting blood, or persistent severe stomach pain.

Comparison: Topical vs. Oral NSAIDs

Topical NSAIDs like Voltaren gel are often chosen to lower the risk of systemic side effects, particularly those affecting the GI tract. Studies indicate that topical diclofenac has a better GI safety profile compared to oral diclofenac.


Feature	Topical Voltaren Gel	Oral Diclofenac
Systemic Absorption	Low (around 6% of oral dose)	High (100%)
Risk of GI Side Effects	Significantly lower	Significantly higher
Common GI Issues	Stomach pain, diarrhea, constipation, gas	Dyspepsia, diarrhea, abdominal pain, nausea
Serious GI Events Risk	Lower, but still present (Black Box Warning)	Greater than 10-fold increased risk for patients with prior ulcer history

Research comparing the two forms has shown significantly fewer gastrointestinal adverse events with topical diclofenac (25.4%) than with oral diclofenac (39.0%). Specific issues like dyspepsia and diarrhea were less frequent in the topical group.

Who Is at Higher Risk?

Certain individuals face a higher risk of NSAID-related GI side effects, even with topical application. Risk factors include:

Older Age: People over 65 have a greater susceptibility.
History of GI Issues: A past of peptic ulcers or GI bleeding raises the risk significantly, with patients having a history of stomach ulcers facing a more than 10 times higher risk of bleeding from NSAIDs.
Concomitant Medications: Using other drugs like oral corticosteroids, anticoagulants, other NSAIDs (including aspirin), or certain antidepressants (SSRIs) increases the risk of bleeding.
High Dosage or Long Duration: Exceeding the recommended dose or using the gel for prolonged periods increases systemic exposure and risk.
Alcohol Consumption: Combining alcohol with NSAIDs can worsen stomach problems.
Poor General Health: Individuals in poor health are at greater risk.

Conclusion

Despite being a topical application, the diclofenac in Voltaren gel is absorbed into the bloodstream and can cause diarrhea and other GI side effects. The risk is considerably lower than with oral diclofenac, making the gel a preferred option for some, especially those concerned about digestive problems. However, a risk of serious GI complications, including bleeding and ulcers, remains with all NSAIDs. Individuals with risk factors, such as advanced age or a history of ulcers, should be particularly cautious. Use the minimum effective dose for the shortest duration. If you experience persistent or severe diarrhea, stomach pain, or signs of bleeding, stop use and contact a healthcare professional immediately.

For more detailed drug information, you can visit the FDA's drug information portal.

Frequently Asked Questions

Diarrhea is listed as a potential side effect of Voltaren gel, but it is less common than with oral diclofenac. Most side effects of the gel are application site reactions like skin irritation.

Even though Voltaren gel is applied to the skin, a small amount of the active ingredient, diclofenac, is absorbed into the bloodstream. This systemic absorption allows the drug to affect other parts of the body, including the gastrointestinal tract, potentially causing side effects like diarrhea.

Mild diarrhea may resolve as your body adjusts. However, you should drink plenty of fluids to avoid dehydration. If the diarrhea is severe, persistent, or accompanied by other symptoms like severe stomach pain or bloody stools, stop using the gel and contact your doctor immediately.

Yes, topical NSAIDs like Voltaren gel are generally considered safer for the stomach than oral NSAIDs like ibuprofen or naproxen because they result in much lower systemic drug levels, leading to fewer gastrointestinal side effects.

You should use extreme caution. A history of peptic ulcer disease is a major risk factor for serious NSAID-related GI complications. Consult your doctor before using Voltaren gel if you have a history of ulcers or GI bleeding.

Signs of a serious gastrointestinal event include severe stomach pain that doesn't go away, black or tarry stools, coughing up blood, or vomit that looks like coffee grounds. If you experience any of these, seek emergency medical help.

Yes, drinking alcohol while using any NSAID, including Voltaren gel, can worsen digestive side effects and increases your risk of more serious stomach issues like bleeding.