Protocol · Digestive
Irritable Bowel Syndrome (IBS) Protocol
Peppermint Oil and Probiotics are the core of this stack, with 2 supporting supplements. Each row gives the amount the protocol lists and the grade our evidence database holds for that supplement in Irritable Bowel Syndrome (IBS).
We are re-verifying the studies cited on protocol pages; only confirmed citations are shown.
The stack
4 supplements · 2 graded · 1 graded A · 2 confirmed studies
| Grade | Supplement | Amount listed | Why it’s in the stack | Evidence on file | Shop |
|---|---|---|---|---|---|
| Primary stackThe core of this protocol | |||||
| Peppermint Oil | Amount listed: 200 mg enteric-coated capsules, 2–3× daily | Menthol blocks calcium channels in intestinal smooth muscle, producing direct antispasmodic effects
| Grade A for Irritable Bowel Syndrome Symptoms7 studies · 392 people | ||
Confirmed studies for Peppermint Oil (titles as PubMed lists them) | |||||
| Probiotics | Amount listed: 10–20 billion CFU daily (multi-strain) | Restores gut microbiome balance, strengthens intestinal barrier integrity, and modulates gut-brain axis signaling
| Grade B for Abdominal Pain2,359 people | ||
| Supporting stackListed as additions to the core | |||||
| Psyllium Fiber | Amount listed: 5–10 g daily with plenty of water | Soluble fiber normalizes stool consistency and transit time through water absorption and bulk formation | Not graded yet | ||
Confirmed studies for Psyllium Fiber (titles as PubMed lists them) | |||||
| Iberogast (STW 5) | Amount listed: 20 drops 3× daily | Nine-herb combination modulates GI motility, reduces visceral hypersensitivity, and has anti-inflammatory effects | Not graded yet | ||
Shop the evidence-backed picks
The collection holds the supplements we grade A or B for its theme, in third-party tested products where the catalog has them. It opens in our Fullscript store. You can look through it without signing in; Fullscript asks for a free account to order.
Or shop one supplement
The 2 supplements in this protocol graded A or B. Each opens third-party tested products, matched to the dose above where we can.
- Grade A
- Grade B
We earn from purchases made in our Fullscript store, and links to Fullscript, iHerb or Thorne carry our referral, so we may earn a commission at no extra cost to you. Grades come from the research and never change based on what we earn. Full disclosure
How this protocol works
In plain language
IBS involves a disrupted connection between your brain and gut. Your intestines become hypersensitive, overreacting to normal signals with pain, bloating, and altered bowel habits (diarrhea, constipation, or both). The gut microbiome is often imbalanced, and the enteric nervous system sends too many pain signals.
- Peppermint oil (enteric-coated capsules) relaxes the smooth muscle of your intestines by blocking calcium channels. This stops painful spasms and cramping. Studies show significant improvement in abdominal pain—it's one of the best-studied IBS treatments.
- Probiotics restore healthy gut bacteria balance. They strengthen the intestinal lining, reduce inflammation, and improve gut-brain communication. Multi-strain formulas or specific strains like B. infantis 35624 work best.
- Psyllium fiber is a soluble fiber that helps normalize bowel movements in both IBS-D and IBS-C. It absorbs water to bulk up loose stools and softens hard stools.
- Iberogast is a German herbal combination that has been used for decades. It calms intestinal spasms, reduces inflammation, and addresses both stomach and intestinal symptoms.
Expected timeline: Peppermint provides relief within 1-2 hours of dosing. Probiotic benefits develop over 4-8 weeks. Fiber effects begin within days but require consistent use.