Can Voltaren Cause Diarrhea? Understanding the Link

October 8, 2025 •

4 min read

In clinical trials, gastrointestinal issues like diarrhea occurred in 1% to 10% of patients taking diclofenac, the active ingredient in Voltaren [1.4.3]. So, can Voltaren cause diarrhea? Yes, it is a recognized and common side effect of this medication.

Quick Summary

Voltaren (diclofenac) commonly causes gastrointestinal side effects, including diarrhea. This occurs because it inhibits prostaglandins, which protect the stomach lining.

Key Points

Direct Link: Yes, Voltaren (diclofenac) is known to cause diarrhea as a common gastrointestinal side effect [1.2.2, 1.2.3].
Mechanism: It happens because Voltaren, an NSAID, inhibits prostaglandins, which help protect the lining of your stomach and intestines [1.6.1].
Incidence Rate: Diarrhea is a common adverse reaction, reported in approximately 1% to 10% of patients taking oral diclofenac [1.4.3].
Oral vs. Topical: The risk of diarrhea is significantly higher with oral Voltaren tablets compared to the topical Voltaren gel [1.7.1, 1.7.2].
Serious Risks: While often mild, diarrhea can be a sign of a more serious issue like GI bleeding or ulcers, which are known risks for all NSAIDs [1.3.3].
When to See a Doctor: Contact a doctor if diarrhea is severe, persistent, or accompanied by symptoms like bloody stools or severe stomach pain [1.3.1].
Management: Taking Voltaren with food and staying hydrated can help manage mild symptoms, but always consult a doctor before stopping medication [1.3.4, 1.5.6].

What is Voltaren and How Does It Work?

Voltaren is a brand name for diclofenac, a widely used nonsteroidal anti-inflammatory drug (NSAID) [1.2.1]. It is prescribed to treat pain, inflammation, and swelling associated with conditions like arthritis, menstrual cramps, and migraines [1.8.4]. Diclofenac works by inhibiting cyclooxygenase (COX) enzymes, specifically COX-1 and COX-2 [1.6.4]. These enzymes are responsible for producing prostaglandins, which are compounds that contribute to inflammation, pain, and fever [1.6.2]. By blocking COX enzymes, Voltaren effectively reduces these symptoms [1.6.2].

However, prostaglandins also play a protective role in the body, particularly in the gastrointestinal (GI) tract. They help maintain the protective lining of the stomach and intestines [1.6.1]. The inhibition of these protective prostaglandins is the primary reason why NSAIDs like Voltaren can lead to a range of GI side effects [1.6.1].

The Link Between Voltaren and Diarrhea

Diarrhea is listed as a common side effect of taking oral Voltaren (diclofenac) [1.2.2, 1.3.7]. Gastrointestinal disturbances, including abdominal pain, constipation, dyspepsia (indigestion), flatulence, heartburn, nausea, and vomiting, are among the most frequently reported adverse reactions, occurring in approximately 1% to 10% of patients [1.4.3].

The mechanism behind this is directly related to Voltaren's primary function. By reducing the levels of prostaglandins throughout the body, Voltaren can disrupt the normal function and integrity of the lining of the stomach and intestines [1.6.4]. This can lead to inflammation, changes in fluid absorption, and increased motility in the gut, all of which can manifest as diarrhea [1.2.1]. For many people, this side effect is mild and may resolve as their body adjusts to the medication [1.2.1]. However, for others, it can be more persistent or severe.

Severity and Associated Risks

While often mild, diarrhea can sometimes be a symptom of more severe underlying GI problems caused by NSAIDs. All NSAIDs, including Voltaren, carry a black box warning from the FDA for an increased risk of serious gastrointestinal events like bleeding, ulceration, and perforation (holes) of the stomach or intestines [1.2.1, 1.3.3]. These events can occur at any time during treatment and without warning symptoms [1.4.1].

Symptoms that should prompt immediate medical attention include:

Bloody or black, tarry stools [1.3.1]
Vomiting blood or a substance that looks like coffee grounds [1.3.1]
Severe stomach pain that doesn't go away [1.4.5]
Diarrhea accompanied by signs of liver problems, such as jaundice (yellowing of the skin or eyes), dark urine, or severe fatigue [1.2.1]

Oral vs. Topical Voltaren (Voltaren Gel)

It's important to distinguish between oral diclofenac and topical forms like Voltaren Gel. The risk of systemic side effects, including diarrhea, is significantly lower with topical applications [1.7.2]. A comparative study found that GI adverse events were much more common with oral diclofenac than with a topical solution (39.0% vs. 25.4%), with diarrhea occurring in 13.4% of oral users compared to just 6.5% of topical users [1.7.1]. While topical use can still lead to systemic absorption, the amount is much less, making GI side effects less likely [1.7.6].

Managing Diarrhea Caused by Voltaren

If you experience mild diarrhea while taking Voltaren, there are several steps you can take:

Take with Food: Taking Voltaren with food can help reduce stomach upset and irritation [1.3.4].
Stay Hydrated: Drink plenty of fluids to prevent dehydration, which can result from diarrhea [1.5.6].
Eat Bland Foods: Foods like bananas, rice, applesauce, and toast (the BRAT diet) can help firm up stools.
Consult Your Doctor: Do not stop taking your prescribed medication without first talking to your healthcare provider. They may adjust your dose or suggest an alternative [1.5.1]. If diarrhea is severe or persistent, it's crucial to seek medical advice [1.5.6]. In some cases, a doctor might prescribe a gastro-protective agent like a proton pump inhibitor (PPI) to take alongside the NSAID, although this is more common for preventing ulcers [1.5.1].

Comparison of Common Pain Relievers


Medication	Class	Mechanism of Action	Common GI Side Effects	Risk of Diarrhea
Voltaren (Diclofenac)	NSAID	Inhibits COX-1 and COX-2 [1.6.4]	Heartburn, indigestion, ulcers, bleeding [1.4.3]	Common (1-10%) [1.4.3]
Ibuprofen (Advil, Motrin)	NSAID	Inhibits COX-1 and COX-2	Similar to Diclofenac, including heartburn and stomach pain [1.8.4]	Possible
Naproxen (Aleve)	NSAID	Inhibits COX-1 and COX-2	Similar to other NSAIDs, may be slightly less risky for heart issues but still carries GI risk [1.8.3, 1.8.4]	Possible
Celecoxib (Celebrex)	COX-2 Inhibitor	Selectively inhibits COX-2 [1.8.4]	Lower risk of stomach ulcers than traditional NSAIDs, but risk still exists [1.8.4]	Possible, but may be less than non-selective NSAIDs
Acetaminophen (Tylenol)	Analgesic	Different from NSAIDs; not anti-inflammatory [1.8.2]	Very low risk of GI issues; main risk is liver damage at high doses [1.8.2, 1.8.3]	Rare

Conclusion

Voltaren (diclofenac) can indeed cause diarrhea as a common side effect, a result of its mechanism of inhibiting protective prostaglandins in the gastrointestinal tract [1.2.3, 1.6.1]. While this side effect is often mild, it's important to monitor symptoms, as it can occasionally signal a more serious issue like GI bleeding or ulcers [1.3.3]. The risk is substantially lower with topical Voltaren gel compared to oral tablets [1.7.1]. If you experience persistent or severe diarrhea, or notice any alarming symptoms like bloody stools, it is essential to contact your healthcare provider immediately [1.3.1].

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional before starting or stopping any medication.

For more detailed information, you can visit MedlinePlus, a service of the National Library of Medicine.

Frequently Asked Questions

Stomach problems like diarrhea and heartburn can begin fairly quickly after starting treatment with Voltaren (diclofenac) [1.2.1].

Usually, the diarrhea is a mild side effect that may go away as your body adjusts [1.2.1]. However, it can sometimes be a sign of a more serious condition like an ulcer or internal bleeding, which requires immediate medical attention [1.3.3, 1.4.5].

Topical forms of diclofenac, like Voltaren Gel, are much less likely to cause systemic side effects like diarrhea compared to oral tablets because less medication is absorbed into the bloodstream [1.7.2]. While still possible, the risk is significantly lower [1.7.1].

If the diarrhea is mild, try taking Voltaren with food and ensure you stay hydrated [1.3.4]. If it is severe, persistent, or you see blood in your stool, you should contact your doctor right away [1.3.1].

Yes. Acetaminophen (Tylenol) is not an NSAID and rarely causes gastrointestinal issues [1.8.2]. Selective COX-2 inhibitors like Celecoxib may also have a lower risk of GI side effects compared to traditional NSAIDs like Voltaren [1.8.4].

You should not stop taking a prescribed medication without first consulting your healthcare provider [1.5.1]. They can assess the severity and advise on the best course of action, which might include dose adjustment or switching to a different medication.

Other common gastrointestinal side effects include abdominal pain, constipation, heartburn, indigestion (dyspepsia), gas (flatulence), nausea, and vomiting [1.4.3].