Experts Explain What Happens If You Take Too Many Probiotics

You *can* have too much of a good thing.

Can you take too many probiotics? Experts explain the side effects that can indicate you've got a probiotics overload.

You’ve probably heard of probiotics for their ability to heal everything from stomach troubles to skin concerns. And they can — with the right dosage. But having too much of a good thing can sometimes lead to its own set of issues. So can you take too many probiotics?

Probiotics are live microorganisms that are a natural part of your gut microbiome, or the community of trillions of bacteria that live in your digestive tract, according to registered dietitian and functional medicine expert Alana Kessler, RDN. Having a healthy balance of gut bacteria (which probiotics can help maintain) means a better-regulated digestive system, clearer skin, and a stronger immune system — hence why some people turn to probiotic supplements or eat naturally probiotic-rich foods like yogurt and kombucha. But an imbalanced microbiome can have the opposite effect: You might notice stomach problems, mood changes, lowered immunity, and more, says dietitian Chelsea McCallum, who works with probiotic snack company BelliWelli.

One way you can throw your gut’s microbiome out of wack? By having too many probiotics in your system, says Kessler. Think about it like exercise — some activity is healthy for your body, but exercising all day, every day won’t make you feel good. Probiotics are similar, says McCallum. Overloading on the microorganisms by taking more than the recommended dose (McCallum recommends a maximum 10 billion CFU, or colony forming units, several days a week) can actually mean you have too much good bacteria at work in your stomach, which can overwhelm your gut’s ability to function normally.

Balance is the key to success when it comes to your gut microbiome,” McCallum tells Bustle. “With the abundance of probiotics available, it can be easy to overdo it.” And you’ll probably feel it if you overdo it on the supplements, adds Kessler. From bloating to brain fog, here are the signs that you’ve taken too many probiotics.

1. Gas

Taking too many probiotics can cause some of the problems you were hoping to remedy in the first place like gas issues, says Kessler. You might experience gas when you first start probiotics as your body adjusts to the new bacteria, according to 2010 research in the American Journal of Health-System Pharmacy. If that’s the cause of your excess flatulence, then it should subside in a few weeks as your body gets used to the supplement.

But if the gas persists, it could be a sign that you’re dealing with a bacterial overgrowth condition called small intestinal bacterial overgrowth (SIBO). Research shows that those excess microorganisms can go on a feeding frenzy whenever you eat, fermenting the food in your digestive tract into extra air. The end result? A lot more unpleasant flatulence than usual, according to Kessler.

2. Bloating

The same goes for bloating, says Kessler. Like gas, it’s a common side effect when you first start taking the supplements. But if it lasts longer than a few weeks, it could be another sign that your probiotics are producing extra air, which can lead to uncomfortable bloating.

3. Stomach Aches Or Cramps

An upset stomach can go hand-in-hand with symptoms like gas and bloating, says McCallum, and should fade in a few weeks if it’s just a matter of your body adjusting to your new probiotics. But if unwelcome bloat continues living in your gut, it can cause everything from nausea to cramping in the longer term, and could be a sign that your probiotics aren’t agreeing with you.

4. Brain Fog

All that extra gas hanging out in your gut doesn’t just impact your body — it can also effect your mind due to the gut-brain connection, says Kessler. Research in the American Journal of Health-System Pharmacy found that having excess gas from a bacterial overgrowth can impact your ability to think clearly by messing with your short-term memory, judgement, and ability to concentrate. So if you’re noticing more brain fog after giving supplements a go, it might be a sign that you need to cut back or pause probiotics.

5. Diarrhea

Another common sign you’re in probiotic overload? Urgent trips to the bathroom, says McCallum. Like other stomach-related side effects, diarrhea should subside once your body adjusts to trying probiotics for the first time. But persistent bathroom problems could be a sign that your probiotics are throwing your microbiome out of balance more profoundly, which can impair your digestive tract’s functioning and set the stage for chronic pooping problems.

6. Infection

If you have lowered immune function, taking probiotics can up your risk of infections, cautions Kessler. Though this isn’t a common sign of overloading the supplement, it can have serious consequences if you have a condition that impacts your immune system, just had surgery, or otherwise had a long hospital stay. That’s because your gut is closely tied to the health of your immune system, so interfering with your microbiome could likewise impact its function.

If this sounds like you, Kessler recommends consulting with your doctor about probiotics before trying them yourself. Some strains are better than others depending on what conditions you have, she adds, so you can also work with your doc to determine what type of probiotic is best for your system.

How To Deal

In some cases, lowering your probiotic dosage or trying a different strain of bacteria could be the solution, says Kessler. But if you have a bacterial overgrowth like SIBO on your hands, these unpleasant side effects can persist unless you intervene with treatments like antibiotics to kill off the excess bacteria, says McCallum. “Probiotics are not a magic pill that everyone should be taking, specially for individuals with SIBO,” she tells Bustle. “In cases where you need to take an antibiotic to kill off extra bacteria in the small intestine, delivering more bacteria to the body is counterproductive.” If that’s the case, ditching probiotics altogether may be your best bet, she says.

Studies referenced:

Ducowicz, A. (2007). Small Intestinal Bacterial Overgrowth. Gastroenterology & Hepatology. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3099351/

Guinane, C. (2013). Role of the gut microbiota in health and chronic gastrointestinal disease: understanding a hidden metabolic organ. Therapeutic Advances in Gastroenterology, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3667473/

Krajieck, E. (2016). Small Intestinal Bacterial Overgrowth: A Primary Care Review. Mayo Clinic Proceedings, https://www.mayoclinicproceedings.org/article/S0025-6196(16)30589-4/pdf

Lerner, A. (2019). Probiotics: If It Does Not Help It Does Not Do Any Harm. Really? Microorganisms, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6517882/

Rao, S. (2018). Brain fogginess, gas and bloating: a link between SIBO, probiotics and metabolic acidosis. Clinical and Translational Gastroenterology, https://journals.lww.com/ctg/Fulltext/2018/06000/Brain_fogginess,_gas_and_bloating__a_link_between.6.aspx

Sachdev, A. (2013). Gastrointestinal bacterial overgrowth: pathogenesis and clinical significance. Therapeutic Advances in Chronic Disease, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3752184/

Salminen, M. (2004). Lactobacillus bacteremia, clinical significance, and patient outcome, with special focus on probiotic L. rhamnosus GG. Clinical Infectious Diseases, https://pubmed.ncbi.nlm.nih.gov/14679449/

Williams, N. (2010). Probiotics. American Journal of Health-System Pharmacy, https://pubmed.ncbi.nlm.nih.gov/20208051/

Wu, H. (2012). The role of gut microbiota in immune homeostasis and autoimmunity. Gut Microbes, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3337124/


Alana Kessler, MS, RDN, a registered dietitian

Chelsea McCallum, APD, an accredited practicing dietitian and nutritionist with probiotic snack company BelliWelli