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ingestible · for sibo (small intestinal bacterial overgrowth)

Partially Hydrolyzed Guar Gum (PHGG)

Reviewed by the Nimbera editorial team · Last updated May 2026

A 2016 randomized trial in the Journal of Gastroenterology found that adding PHGG to rifaximin treatment for SIBO increased eradication rates significantly compared to rifaximin alone (87.5% vs 62.1%), with reductions in bloating and stool irregularity.$20-$35 for a 30-day supply

How to use

Mix 5 grams of PHGG powder (brand: Sunfiber) into 8 oz of water or a smoothie once daily. Can be used during and after antibiotic or herbal SIBO treatment. Odorless and tasteless. Start with 2.5 g and work up over 1-2 weeks.

How it works

Unlike most prebiotics, PHGG is slowly and uniformly fermented in the colon rather than the small intestine, making it safe for SIBO patients. It supports commensal bacteria recolonization post-treatment and appears to enhance the efficacy of antimicrobial therapy when used concurrently.

Where to buy

Sunfiber brand on Amazon, iHerb, Thorne.

Typical cost: $20-$35 for a 30-day supply

Safety notes

Generally very well tolerated. Start low and increase slowly. Do not use inulin, FOS, or other prebiotic fibers during active SIBO treatment as these will feed dysbiotic bacteria. PHGG is an exception due to its colonic fermentation profile.

Drug & supplement interactions

  • Always tell your doctor or pharmacist about any supplements you take.
  • Interactions can occur with prescription medications, blood thinners, and immunosuppressants.
  • Herbal remedies can affect how the body absorbs or metabolises drugs.
  • Check drugs.com interactions checker before starting.

Clinical source

PubMed - Furnari et al. 2010

This information is compiled from primary clinical literature and is for informational purposes only. It is not a substitute for professional medical advice. Read our full disclaimer.