Probiotics and IBS


What do you think of when you hear the word “probiotics”? You may automatically think of fermented foods like yogurt, kefir, or miso (made from fermented soybeans), or perhaps you think of the overflowing probiotic supplement section at your local pharmacy. Either way, the term “probiotics” is a big buzzword when it comes to emerging gut health trends. But what exactly are Probiotics for IBS? Should you be taking probiotics if you have irritable bowel syndrome (IBS)? Let’s take a look at what we know. 

Probiotics are defined by the World Health Organization (WHO) as “live microorganisms, which, when administered in adequate amounts, confer a health benefit to the host” (1). They are typically active culture bacteria (thought of as “good bacteria”), but also include active culture yeasts. Probiotics are naturally present in fermented foods, but they can also be added to make probiotic food and beverage products. There are also dietary probiotic supplements (we’ll get to this monolith shortly!) that can be taken in pill form.

Reading a probiotic supplement label requires you to pull up any dormant science class information from your memory. Each probiotic strain is identified by its genus, species, subspecies, and strain designation. For example, one popular probiotic strain is Bifidobacterium animalis lactis DN-173 010, or its nickname, Bifidus regularis. This is the type of active culture strain that is in the uber-popular yogurt brand, Activia. The most popular and most well studied probiotic strains are Bifidobacterium and Lactobacillus acidophilus. They are often found in dairy products and have been found safe. 


Let’s consider the information available on probiotics to patients with irritable bowel syndrome (IBS). Someone with IBS symptoms may want to take a probiotic supplement or probiotic food to help with diarrhea or constipation. They may also be looking to relieve abdominal pain, bloating, or gas that their irritable bowel syndrome (IBS) has caused. However, is there any evidence that taking probiotics for irritable bowel syndrome (IBS) leads to health benefits? Let’s look at what the experts say. 

The recent American College of Gastroenterology (ACG) guidelines did a meta-analysis on single and multi-strain probiotics used on irritable bowel syndrome (IBS) sufferers. The goal of most of these studies was to improve global IBS symptoms like abdominal pain, bloating, gas, and diarrhea, and/or constipation. The ACG recommends against the use of probiotics for global IBS symptoms as there just isn’t enough consistent evidence. They looked at hundreds of studies on probiotics and irritable bowel syndrome (IBS) before coming to this conclusion. Unfortunately, most of the studies were small in size, single-center, and did not follow the FDA’s guidelines in order to be considered a pharmacological therapy. 

While the studies out there did not give a blanket recommendation for all people with irritable bowel syndrome (IBS), the authors of the guidelines did note that this isn’t really a strong recommendation, as there isn’t a lot of evidence. It’s clearly an emerging field and something we should keep our eyes on. This means that you can’t imply that an individual would not benefit from a probiotic.

The recent American Gastroenterological Association (AGA) guidelines also do not recommend probiotics for the treatment of irritable bowel syndrome (IBS) due to insufficient evidence. They do not say that probiotics will NOT work, as they may be beneficial for certain individuals. The best strain and dose of probiotic for you may depend on your specific microbiome, genes, and diet, so it’s difficult to make blanket statements regarding probiotics and populations. They also recommend working with your healthcare provider to see if a probiotic could provide health benefits for you and your unique needs (3). Bottom line: discuss your irritable bowel syndrome (IBS) symptoms and the use of probiotics with your healthcare provider. 


If you and your healthcare provider do decide on a trial of probiotics for your irritable bowel syndrome (IBS) symptoms, there are a few things to consider when choosing one.

  • Strain: Has it been studied in individuals with irritable bowel syndrome (IBS)? Your best bet may be sticking to Lactobacillus or Bifidobacterium strains, as they are the most well-studied. 

  • Colony Forming Unit (CFU): Typically, you need at least 1 billion CFUs to have a therapeutic effect. However, it really depends on the strain, amount of CFUs studied, and of course the purpose.

  • Survivability: If a probiotic is not strong enough to make it past your stomach acid, then there’s no point in using one. Probiotics need to make it to your intestines to work. 

  • Additional ingredients: Possible allergens or inactive ingredients. Probiotic foods include milk products, which you would want to avoid if you have a dairy allergy. Some probiotics contain inulin, which is a prebiotic. It is also a high FODMAP ingredient. If you’re trialing a Low FODMAP diet, you may need to stop that specific probiotic.

  • Taking and storing as directed: Store it in the refrigerator or a dark, cool place as denoted on the label. If you store differently, this may impact or denature the product. 

  • Side effects: Gas and bloating are the most common side effects of probiotic foods and supplements. If you have a weakened immune system (i.e. you have cancer and are undergoing chemotherapy), there is a risk for infection. 

  • Timing: Probiotics should be taken as directed by your healthcare provider. You should consider if this is a short or long-term supplement, as that may impact your results. 

  • Regulation: Probiotic supplements and foods are a billion-dollar industry, but unfortunately, unlike medications, probiotics and other supplements are not regulated by the FDA. This means that no probiotics have been found to treat, prevent or cure disease. Look for well-studied strains like Lactobacillus and Bifidobacterium


So here’s the million-dollar question, “I have irritable bowel syndrome (IBS). Should I take a probiotic?”

It is still “to be determined” whether everyone with irritable bowel syndrome (IBS) should be taking a probiotic. We don’t have sufficient evidence to say that a specific probiotic strain (or multi-strain) will be beneficial in the treatment of irritable bowel syndrome (IBS). However, it appears to be highly individualized and is worth a discussion with your healthcare provider if it’s something you’d like to try. They may recommend a specific probiotic depending on your unique situation and specific IBS symptoms. Otherwise, continue to consume products with naturally present probiotics, like yogurt and kefir. 



  1. Can Fam Physician. 2005 Nov 10; 51(11): 1455–1457

  2. Am J Gastroenterol 2020;00:1–28.; published online December 14, 2020

  3. AGA Clinical Practice Guidelines on the Role of Probiotics in the Management of Gastrointestinal Disorders. Clinical Practice Guidelines. (n.d.).