How Long Does Diarrhea from Prilosec Last?

October 12, 2025 •

4 min read

Clinical trials reveal that diarrhea is one of the common side effects reported by people taking omeprazole, the active ingredient in Prilosec. The duration of diarrhea from Prilosec is typically short-lived for mild cases, often lasting from a few days to a few weeks.

Quick Summary

Mild diarrhea from Prilosec (omeprazole) is a common side effect that usually resolves within a few days or weeks. Persistent, severe, or bloody diarrhea could signal a more serious issue, such as a C. difficile infection, requiring immediate medical attention.

Key Points

Mild Diarrhea Duration: Mild diarrhea caused by Prilosec (omeprazole) is typically temporary and may last anywhere from a few days to a few weeks.
Severe Diarrhea Warning: Severe, watery, or bloody diarrhea, especially with fever, could be a sign of a Clostridioides difficile (C. diff) infection, which is a rare but serious side effect associated with PPIs.
Long-Term Use Risk: The risk of C. diff infection and associated severe diarrhea increases with long-term Prilosec use.
Management: For mild diarrhea, focus on hydration and dietary changes, like the BRAT diet. Avoid OTC antidiarrheal medications without a doctor's approval.
When to See a Doctor: Seek immediate medical attention if diarrhea is severe, bloody, or does not improve, as this warrants further evaluation.
Do Not Stop Abruptly: Stopping Prilosec suddenly can cause rebound acid production and should not be done without consulting a doctor.

Prilosec, with the generic name omeprazole, is a proton pump inhibitor (PPI) used to treat conditions like gastroesophageal reflux disease (GERD), stomach ulcers, and excess stomach acid. It works by blocking the enzyme in the stomach wall that produces acid, thereby reducing the amount of acid produced. While effective, omeprazole can cause a number of side effects, including gastrointestinal issues like diarrhea. For most individuals, this is a temporary and manageable condition, but understanding the potential duration and risks is crucial for proper management.

The Typical Duration of Mild Prilosec-Induced Diarrhea

When experiencing mild diarrhea shortly after starting Prilosec, the good news is that it is often temporary. According to clinical trial data, these common side effects typically resolve within a few days to a few weeks as your body adjusts to the medication. During this period, it is important to focus on supportive care and hydration.

Several factors can influence the duration and severity of diarrhea, such as your general health, other medications you may be taking (especially antibiotics, which can increase risk), and whether you have any pre-existing gastrointestinal conditions. If the diarrhea is mild and you are otherwise feeling well, you can often manage it with simple dietary changes and lifestyle adjustments.

Managing Diarrhea Caused by Prilosec

If you experience mild diarrhea while on Prilosec, several steps can help alleviate the symptoms and prevent dehydration:

Stay Hydrated: Drink plenty of fluids, such as water, clear broth, and electrolyte-rich beverages, to replace lost fluids and minerals.
Dietary Adjustments: Consider a bland diet for a few days, focusing on foods like bananas, rice, applesauce, and toast (the BRAT diet). Avoid fatty, fried, and spicy foods that can irritate the digestive system.
Timing of Dose: While omeprazole works best on an empty stomach, if nausea and diarrhea are an issue, some people find relief by taking it with or after a meal, though this may decrease its effectiveness slightly. Always consult your doctor or pharmacist first.
Consult Before Using Antidiarrheal Medications: Do not take over-the-counter (OTC) antidiarrheal medications like loperamide (Imodium A-D) without first speaking to a healthcare professional, as they may mask symptoms of a more serious infection.

The Risk of More Serious Diarrhea

While mild, short-term diarrhea is common, Prilosec use, especially long-term, is associated with a higher risk of developing a more serious bacterial infection known as Clostridioides difficile (C. diff). This infection can cause severe, watery diarrhea and requires immediate medical attention.

When to Seek Immediate Medical Help

Contact your doctor immediately if you experience any of the following symptoms:

Severe, watery diarrhea that does not improve
Diarrhea with blood or pus in your stool
A persistent fever
Severe abdominal pain or cramping

These symptoms can be signs of a C. diff infection, which needs to be diagnosed and treated by a healthcare provider.

Comparison of Diarrhea Symptoms

It's important to differentiate between typical mild side effects and a more severe condition like a C. diff infection. The table below outlines key differences.


Feature	Mild Prilosec-Induced Diarrhea	Clostridioides difficile (C. diff) Infection
Onset	Often starts within days or a couple of weeks of starting medication.	Can occur anytime, but more common with prolonged use.
Duration	Resolves within a few days to weeks as body adjusts.	Persistent, lasting longer than a couple of weeks without treatment.
Severity	Usually not severe; manageable with dietary changes.	Can be severe and debilitating; watery stools, fever, and pain.
Stool Characteristics	Loose stools or increased frequency.	Watery or bloody stools.
Associated Symptoms	May include mild abdominal pain, nausea, or gas.	High fever, severe abdominal pain, nausea, loss of appetite, and fatigue.

Conclusion: When to Call Your Doctor

For most people, mild diarrhea from Prilosec is a temporary side effect that resolves as the body adapts to the medication within a few weeks. Staying well-hydrated and making simple dietary adjustments can help manage the symptoms during this time. However, it is crucial to recognize that persistent or severe diarrhea, especially if accompanied by fever, blood in the stool, or increasing abdominal pain, is a red flag for a more serious condition, such as a C. difficile infection. If you experience these severe symptoms, contact your healthcare provider immediately. Always discuss any bothersome or long-lasting side effects with a medical professional to ensure safe and effective treatment. For more information, the U.S. National Library of Medicine provides details on omeprazole's usage and side effects.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult a healthcare provider for diagnosis and treatment. Do not stop taking a prescribed medication without first consulting your doctor.

Frequently Asked Questions

Yes, diarrhea is a common side effect of Prilosec (omeprazole). Clinical studies have reported that some individuals experience mild diarrhea, as well as other gastrointestinal issues like nausea, abdominal pain, and gas.

For most people, mild diarrhea from Prilosec is temporary. It typically resolves within a few days to a few weeks as the body adjusts to the medication.

If your diarrhea is severe, watery, or contains blood or pus, you should contact your doctor immediately. This could be a symptom of a Clostridioides difficile infection, which requires prompt medical attention.

You should not take over-the-counter antidiarrheal medications without first consulting your doctor. Antidiarrheals may mask the symptoms of a serious infection like C. diff.

Yes, long-term use of Prilosec is associated with an increased risk of developing a serious bacterial infection called Clostridioides difficile (C. diff), which causes severe diarrhea.

Signs of a C. diff infection include severe, watery, or bloody diarrhea, a high fever, and abdominal pain that does not go away. These symptoms warrant immediate medical evaluation.

To manage mild diarrhea, stay well-hydrated with water and electrolyte drinks. Eating bland, easily digestible foods, like bananas and rice, can also help. Avoid spicy, fatty, or acidic foods.