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Probiotics for IBS: What You Should Know

Written by Dr. Michael Ruscio, DC on April 25, 2025

Written by Dr. Michael Ruscio, DC on April 25, 2025 — Reviewed by Hilary Watts

• What Are Probiotics?|
• Do Probiotics Improve IBS Symptoms?|
• Which Probiotic Is Best for IBS?|
• When to Contact a Healthcare Provider|

If you’re one of the 1 in 5 Americans dealing with irritable bowel syndrome (IBS) 1, there’s good news: Probiotics may offer real relief. A growing body of research shows that probiotics are both safe and effective for easing IBS symptoms—without the side effects that often come with other treatments. 

Let’s dive into why probiotics are a smart, science-backed option if you’re struggling with IBS.

What Are Probiotics?

Probiotic bacteria are live microorganisms in your digestive system that have beneficial effects on your health. Probiotics have been shown in many recent studies and double-blind clinical trials to improve IBS symptoms 2 3. 

Research shows that probiotics can help:

• Improve stool consistency and regulate bowel movements 4 5 6
• Relieve bloating, abdominal pain, flatulence 3 4 7

This is great news because there’s no effective pharmaceutical treatment for irritable bowel syndrome. That’s why many patients and clinicians are turning to probiotics—and seeing encouraging results.

Snapshot: Probiotic Categories & Strains

Along with an anti-inflammatory diet, such as a Paleo or low FODMAP diet, using a combination of probiotics is one of the primary approaches I recommend for IBS patients. 

As I discuss more fully in my book Healthy Gut, Healthy You, the most important probiotic strategy for IBS (or any digestive problem) is to include a diversity of high-quality probiotics. 

Though there are hundreds of probiotic supplements on the market, most probiotics fall into one of these three categories:

• Lactobacillus and Bifidobacteria blends, including different strains of probiotics such as L. acidophilus, L. plantarum, B. infantis, and B. lactis
• Saccharomyces boulardii (a beneficial yeast)
• Soil-based probiotics, usually Bacillus species

Using one type of probiotic is good, but using all three different probiotics together allows them to work synergistically to improve your gut health. We call this approach triple therapy and have used it for many years in the clinic for a range of digestive conditions, including IBS.  

Do Probiotics Improve IBS Symptoms?

It’s easy to underestimate probiotics, but their impact goes well beyond basic digestive support. When it comes to IBS, the science is clear: Probiotics can help. Multiple high-quality meta-analyses and clinical trials consistently show that probiotics improve IBS symptoms—making them a research-backed option worth considering.

Probiotics Can Improve Overall IBS Symptoms

Five separate meta-analyses (the highest quality scientific evidence) have shown the efficacy of probiotics for IBS, with very few side effects 2 3 4 7 8. 

In these studies, people given probiotic supplements showed significant improvements in IBS symptoms, including:

• Diarrhea, or loose stools
• Constipation 
• Bloating and abdominal pain
• Flatulence or gas
• Fatigue and difficulty sleeping

But let’s take a closer look at how probiotics can improve each of these symptoms specifically. 

Probiotics Can Reduce Bloating & Abdominal Pain

Bloating, abdominal pain, and cramping are among the most frustrating symptoms of IBS. Fortunately, probiotic research is promising for these. For example,

• A meta-analysis (study of studies) showed that probiotics can be a beneficial therapy for reducing pain and discomfort in people with IBS 9.
• A randomized controlled trial (gold-standard study) showed that probiotics can significantly reduce abdominal pain and distention—when the belly gets visibly bigger—in IBS patients 10. Sometimes, distension is paired with bloating—the noticeable feeling of fullness or pressure in the abdomen. 

Probiotics Can Help Relieve IBS-Related Diarrhea

Diarrhea can be a debilitating IBS symptom. Fortunately, there is evidence that probiotics can help relieve IBS-related diarrhea. Studies have shown:

• The soil-based probiotic Bacillus coagulans can reduce diarrhea and stool frequency in people with IBS 5. 
• People with small intestinal bacterial overgrowth (a condition that overlaps heavily with IBS) may have less diarrhea after taking the probiotic yeast, Saccharomyces boulardii 6. 

Probiotics Can Improve Constipation Symptoms

Constipation can be tenacious and miserable. Fortunately, probiotics can help improve stool frequency and regularity in patients with constipation 4 11. 

In one meta-analysis, probiotics not only significantly improved constipation—they also increased good bacteria in the gut 12. 

Which Probiotic Is Best for IBS?

Probiotics don’t work like medications, so you don’t have to get granular about choosing specific strains to improve your IBS symptoms (or any other health condition). Instead, all well-researched probiotics can provide general health benefits to your gut environment, possibly by:

• Increasing the bacterial diversity, or health, of your gut flora 13
• Fighting pathogens (harmful bugs) and their toxins 14 15
• Promoting faster recovery from imbalances in your gut microflora, which may be a root cause of IBS symptoms 16
• Promoting a healthy gut immune system 17
• Reducing gut inflammation 18
• Encouraging the growth of a healthier gut microbiome 19
• Reducing leaky gut 20

While you don’t need to worry about strain-specificity, you should be wary of quality. Here are some tips for choosing your probiotic.

Choose Probiotic Supplements With:

• A clearly stated list of species
• A clearly stated number of colony-forming units (CFUs) in the billions
• A label stating they are free of common allergens and other substances you may wish to avoid (e.g., gluten-free, non-GMO, vegan)
• A Good Manufacturing Practices (GMP) certification
• Third-party lab testing
• A manufactured date or an expiration date

Pro Tip: Keep an eye out for prebiotic content, as prebiotics may exacerbate gut symptoms for those with more sensitive guts. We typically recommend keeping daily prebiotic intake to around 3–5 grams in these cases. 

Probiotic Dosing for IBS

After years of clinical experience and parsing the research, my team and I have distilled all that we’ve learned into this simple probiotic protocol:

If you’re bracing for a long list of probiotic “rules,” you’re in luck— taking them is actually much simpler than most people think. 

There’s a lot of online advice on when and how to take probiotics, but much of it isn’t backed by solid research. The good news is you don’t need to worry about perfect timing, whether you’ve eaten, or even if the bacteria are alive. 

What really matters is this: Try a quality probiotic, stick with it for a few weeks, and notice how you feel. That’s the kind of feedback that counts most.

Can Probiotics Make IBS Worse at First?

It’s possible to experience a temporary flare-up of symptoms when you first start taking probiotics—this is typically due to what’s known as a “die-off” reaction. This occurs when probiotics help eliminate harmful bacteria in your gut. As your body clears them out, you might briefly feel worse, like getting cold or flu symptoms, feeling tired, or getting headaches, brain fog, or skin breakouts—because your immune system is jumping in to clean up the mess.

However, these symptoms usually don’t last long. Within the first week or so, you should have a sense of whether the probiotics are helping. If symptoms significantly worsen or continue beyond the initial adjustment period, it could indicate that the particular probiotic you’re using isn’t the best fit for your gut. In these cases, it’s worth considering switching to a different product, as some probiotics may contain additives or certain strains that don’t agree with your system.

Remember, every gut is different, and what works for one person may not work for another. If you experience a negative reaction, it doesn’t mean probiotics won’t help—just that a different option might be better suited to your needs.

When to Contact a Healthcare Provider

Probiotics can improve many IBS symptoms, including bloating, abdominal pain, diarrhea, constipation, and more. Including probiotics and an anti-inflammatory diet in your regular routine is likely to reduce your IBS symptoms and leave you feeling better. 

If you’re ready to give probiotics a try, start with one from each category and give your body a few weeks to respond. Most people know within a month if probiotics are helping—and many notice improvement sooner. If you want additional support or guidance, our team is here to help.

The Ruscio Institute has developed a range of high-quality formulations to help our clients and audience. If you’re interested in learning more about these products, please click here. Note that there are many other options available, and we encourage you to research which products may be right for you. The information on DrRuscio.com is for educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment.