Digestive
Medicines for Small intestinal bacterial overgrowth (SIBO)
An excess of bacteria in the small intestine, causing bloating, wind and digestive symptoms — treated with antibiotics and by addressing any underlying cause.
Education and reference only. This explains which medicines are used and why, in plain language — it deliberately contains no doses and is not a substitute for advice from your doctor or pharmacist. Always discuss your own treatment with a qualified clinician, and check the BNF and the product labelling for prescribing detail.
Quick answer
What is Small intestinal bacterial overgrowth (SIBO)?
Small intestinal bacterial overgrowth (SIBO) is a condition in which there are too many bacteria, or the wrong types, in the small intestine — which normally has relatively few. This overgrowth interferes with digestion and can cause symptoms such as bloating, excess wind, tummy pain or discomfort, diarrhoea and, if it affects nutrient absorption, weight loss or deficiencies.
- How it is treated: Treatment usually involves a course of antibiotics to reduce the excess bacteria, which improves symptoms in many people, along with addressing any underlying cause that predisposes to it — as SIBO can recur if the cause remains.
- Self-care: Following the treatment plan, addressing any underlying cause, correcting nutrient deficiencies with dietitian support where needed, and dietary strategies for some people all help.
- When to seek help: See a GP for persistent bloating, wind, tummy discomfort and altered bowel habit, especially with weight loss or after abdominal surgery, so the cause can be assessed and other conditions excluded.
What it is
Small intestinal bacterial overgrowth (SIBO) is a condition in which there are too many bacteria, or the wrong types, in the small intestine — which normally has relatively few. This overgrowth interferes with digestion and can cause symptoms such as bloating, excess wind, tummy pain or discomfort, diarrhoea and, if it affects nutrient absorption, weight loss or deficiencies. It often develops because something has disturbed the normal movement or structure of the small bowel — for example previous abdominal surgery, certain conditions affecting gut movement (such as some cases of diabetes or scleroderma), or structural problems. Its symptoms overlap with other conditions such as irritable bowel syndrome, so it is not always straightforward to identify. It may be diagnosed with a breath test or, sometimes, on the basis of symptoms and response to treatment.
How it is treated
Treatment usually involves a course of antibiotics to reduce the excess bacteria, which improves symptoms in many people, along with addressing any underlying cause that predisposes to it — as SIBO can recur if the cause remains. Correcting any nutritional deficiencies (such as certain vitamins) is important where absorption has been affected, sometimes with dietitian support. Dietary approaches may help some people. Because SIBO tends to recur, ongoing management sometimes includes repeated or rotating treatment and measures to support normal gut function. Care is often guided by a gastroenterologist, particularly where there is an underlying condition or persistent symptoms. Distinguishing it from, and it sometimes coexisting with, conditions like IBS is part of the assessment.
For this condition, these medicines
Medicine classes used for Small intestinal bacterial overgrowth (SIBO)
Each links to a full, dose-free guide — what it is, how it works, who can and cannot use it, side effects, interactions and FAQs.
Beyond medication
Lifestyle and self-care
Following the treatment plan, addressing any underlying cause, correcting nutrient deficiencies with dietitian support where needed, and dietary strategies for some people all help. Managing any predisposing condition reduces recurrence.
When to get help
When to see a doctor
See a GP for persistent bloating, wind, tummy discomfort and altered bowel habit, especially with weight loss or after abdominal surgery, so the cause can be assessed and other conditions excluded.
Not sure how urgent it is? It is always OK to call NHS 111 for advice, day or night.
Answers
Small intestinal bacterial overgrowth (SIBO): frequently asked questions
What causes SIBO?
It often develops when something disturbs the normal movement or structure of the small bowel — such as previous abdominal surgery, conditions affecting gut movement, or structural problems — allowing bacteria to overgrow.
How is SIBO treated?
Usually with a course of antibiotics to reduce the excess bacteria, along with addressing any underlying cause and correcting nutrient deficiencies. It can recur, so ongoing management is sometimes needed.
Sources
Where this is drawn from
- British Society of Gastroenterology — guidance
- NHS — related digestive conditions
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