Probiotics Cause SIBO - Dominick Hussey

Do Probiotics Cause Small Intestinal Bacterial Overgrowth?

A number of my clients ask me whether probiotics cause or may worsen Small Intestinal Bacterial Overgrowth (SIBO). I think this question has come from conflicting commentary on the internet.

The simple answer to this question is no. They do not cause SIBO, and most scientific evidence supports that statement. However, there have been a couple of studies that have come to the opposite conclusion. Some have cited these studies to support their advice or think they cause SIBO. But when you look closely, the findings from the studies are not congruent with the conclusions.

One study is entitled “Effect of Bifidobacterium infantis 35624 (Align) on the Lactulose Breath Test for Small Intestinal Bacterial Overgrowth.

In this study, the researchers gave 19 people a probiotic. After some weeks, the researchers gave the subjects a lactulose breath test. The researchers found that 3 of the 19 participants had a positive breath test for SIBO. Hence, the researcher concludes that probiotics cause SIBO.

However, it is essential to put these findings in the right context.

Firstly a critical part of the results we need to be mindful of is that the three people experienced no significant increase in their symptoms. In other words, despite the positive lab test, the people did not feel worse.

Secondly, we need to be heedful of how probiotics work. The majority do not colonize the gut. They are mainly transient, working through the intestines before dying off or coming out the other end. A transient build-up can cause a positive SIBO breath test.

So, when considering the context of the results, the evidence that probiotics cause or worsen SIBO is poor.

Overall, the vast bulk of research shows that they help SIBO.

Probiotics can help eradicate other harmful bacteria, reduce fungal overgrowth and help reduce leaky gut. More importantly, they have been shown to help minimize digestive symptoms such as bloating, diarrhea and gas. There is also additional evidence that probiotics can improve mood and skin disorders.

So the question of whether probiotics cause SIBO, based on current evidence, the answer is no. A small number of people may have an adverse reaction. If that is the case for you, continue and possibly try a different type of probiotic. For more information, check out my free ebook, Probiotics – Everything You Need To Know Ebook, which explains how probiotics work and how to choose the right one.

What Do You Think?

Do you have more questions about the SIBO and probiotics?

Has taking probiotics made your SIBO worse?

Either way, leave a comment below.

Help And Online Dispensary

If you need extra help, I offer Functional Medicine consultations in person and via telemedicine. To book an appointment or learn more, please call 613 230-0998 or email

If you need to buy supplements, you can do so through our online dispensary.


The information provided in this article is for educational purposes only and is not intended to diagnose or treat any disease. Please do not apply this information without first speaking with your doctor.

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