Rifaximin in diarrhoeal illness
Where it helps, where it does not, and how to use it safely
What is rifaximin?
Rifaximin is a poorly absorbed oral antibiotic that acts locally within the gut. It is limited to non-invasive enteric bacteria.
When rifaximin is appropriate
- Non-invasive traveller’s diarrhoea: moderate diarrhoea without fever, no blood/mucus
- Selected chronic uses (specialist-directed): SIBO, some IBS-D
When rifaximin should NOT be used
- Fever or dysentery
- Bloody diarrhoea
- Suspected invasive infection
- C. diff
- Suspected STEC — risk of HUS
Typical adult dosing (general guidance)
- 200 mg three times daily for 3 days (traveller’s diarrhoea)
Continue ORS alongside treatment.
Safety profile
Common side effects: abdominal discomfort, bloating, nausea. Overuse may promote resistance; recurrent symptoms require reassessment.
Key takeaway: Rifaximin is a niche antibiotic for non-invasive diarrhoea. It is not a broad solution and should be used selectively.