What is SIBO?

Everyone seems to be talking about a “new” digestive condition called SIBO, or small intestinal bacterial overgrowth, at the moment. This difficult disorder is now thought to be the underlying cause of up to 75% of cases of IBS – irritable bowel syndrome, which affects up to one in five people in the UK.

This article will explain exactly what SIBO is, how to test for it and how herbalists treat it using diet, herbs and supplements. If you’re one of those people with IBS who’ve “tried everything” with no luck, this might be worth a read.

Symptoms of SIBO

To put it simply, SIBO happens when bacteria from the large intestine gets into the small intestine. It’s not so much an overgrowth of “bad” bacteria as an overgrowth of the wrong bacteria.

Characteristic symptoms are bloating quickly after a meal, bloating just below the ribs, an intolerance of high fibre foods, abdominal pain and alternating diarrhoea and constipation.

However, there a host of others; nausea, acid reflux, indigestion, food reactions or allergies, anxiety, depression and brain fog to name a few.  

How do I test for it?

So you’re experiencing the above symptoms – how do you know it’s SIBO? Luckily there’s a really simple breath test called the Lactulose hydrogen & methane breath test, which detects the presence of methane or hydrogen-producing bacteria in the small intestine.

This test can be ordered through Genova diagnostics or BioLab UK, and the instructions are very easy to follow. Now let’s get on to what actually causes SIBO in the first place.

What causes it?

So what causes bacteria to move into the small intestine? Long-term antibiotic and antacid use, especially proton pump-inhibitors like omeprazole, is the real culprit here. Antibiotics weaken the immune system and chronic low levels of stomach acid enable the growth of unwanted bacteria in the small intestine.

However, bacteria only move in if there is a problem with the natural movement of the small intestine – something called ‘deficiency of the migrating motor complex’ or MMC. The MMC is a bundle of nerves and muscles that act as a sort of garbage-disposal system, pushing the contents of the small intestine out into the large intestine.

This can malfunction in a range of different situations – diabetes, hypothyroidism or taking opioid painkillers can all cause deficiency of the MMC. But by far the most common cause is acute gastroenteritis, otherwise known as food poisoning, stomach flu or ‘traveller’s diarrhoea’.

There are other less common causes of SIBO like Crohn’s disease, scarring left behind after surgery and accidents which result in trauma to the abdomen. But if you’ve been diagnosed with SIBO, chances are you’ve had food poisoning in the past that, over time, has led to damage to the migrating motor complex of the small intestine.

And it’s the location of the bacteria in the small bowel which unfortunately makes SIBO so hard to treat.

Can’t I just take probiotics?

Probiotics, which inoculate the large bowel with beneficial bacteria, can make SIBO symptoms worse – and prebiotics, special types of fibre that feed intestinal bacteria, definitely do. In some people, however, probiotics can help – you need to find the right strain that works for you.

However, it’s so important to treat SIBO slowly, carefully and properly, to make sure it doesn’t come back. That’s where a well-thought out regime of diet, herbs and supplements comes in.

Herbal treatment for SIBO

We start with a strict low-FODMAP (fermentable carbohydrates and sugar alcohols) diet for one month. This starves the bacteria of their fuel and helps prepare the body for the strong anti-microbial treatment to come. During this first phase, we also use herbs & supplements for digestive and immune support.

In Phase 2 we do a 4-6 week course of strong anti-microbial herbs like oregano, barberry and goldenseal, and in Phase 3 we introduce herbs & supplements to stimulate the MMC, such as ginger, chamomile and peppermint. This 3-phase approach lasts for 3-4 months and makes sure bacteria are safely wiped out, and stay out.

Doing this on your own is difficult, so I recommend getting in touch with a natural health practitioner who knows how to treat SIBO.

By Poppy Burr
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Poppy, BSc MCPP, is a qualified medical herbalist practising from Aljezur and Praia da Luz. To book a consultation, visit
or call on 969 091 683.