Iberogast Formula (Nine-herb German formula): Benefits, Dosage, Safety & Evidence

Frequently asked questions

How does Iberogast work to improve digestion?

Iberogast works through a multi-target mechanism involving the modulation of gastrointestinal motility and tone. The formula acts as a prokinetic to stimulate gastric emptying while simultaneously providing antispasmodic effects to relax intestinal cramping. Key compounds, particularly from Iberis amara, regulate smooth muscle function, while other herbs like chamomile provide anti-inflammatory support to the gastric mucosa. Evidence Level: C.

Can I take Iberogast while pregnant or breastfeeding?

No, Iberogast is considered unsafe during pregnancy and breastfeeding. The formula contains herbs such as Angelica archangelica, which may stimulate uterine contractions, and the liquid extract contains alcohol. Due to these contraindications and a lack of safety data, pregnant women should avoid this product and consult a healthcare provider for alternative options. Evidence Level: D.

What is the recommended dosage for Iberogast?

The standard adult dosage for Iberogast is 20 drops (1 ml) taken three times daily. It should be taken before or with meals mixed in a small amount of liquid, such as water or tea. Dosage for children under 12 years of age must be determined by a healthcare professional based on age and weight. Evidence Level: C.

Does Iberogast interact with other medications?

While specific drug interaction studies are limited, caution is advised. Due to rare reports of liver injury, Iberogast should be used cautiously with other medications known to affect the liver. Additionally, licorice root in the formula may interact with antihypertensive drugs or diuretics by affecting potassium levels. Patients on prescription medications should consult a doctor before use. Evidence Level: C.

Is Iberogast safe for patients with liver disease?

No, Iberogast is contraindicated for patients with existing liver disease. There have been rare reports of liver injury associated with the use of this herbal combination. Consequently, individuals with a history of hepatic impairment or elevated liver enzymes should avoid this product to prevent potential exacerbation of their condition. Evidence Level: C.

PubMed-compiled information sheet

This sheet was compiled from PubMed (NIH) abstracts using AI assistance. Every factual claim is cited to a real PubMed article (see the source list). It has not yet been human-reviewed — confirm with a healthcare provider before use.

Compiled from 30 PubMed articles · model: gemma4:31b

Summary

Iberogast (STW 5) is a multi-herbal preparation used for the management of functional gastrointestinal disorders, including functional dyspepsia and irritable bowel syndrome [PMID:29421817, PMID:23263639].

Background

Iberogast (STW 5) is a fixed combination of nine medicinal plant extracts, including Iberis amara, peppermint, chamomile, and Greater Celandine [PMID:15606389, PMID:16978852, PMID:39132058]. A refined six-herb version known as STW 5-II (Iberogast-N) also exists [PMID:40684457, PMID:41319263].

Active compounds

The formula contains glycosides and flavonoids [PMID:23336345].

Mechanism of action

Iberogast employs a multi-target principle, modulating gastrointestinal motility (relaxing the proximal stomach while increasing antral motility), reducing visceral hypersensitivity, and inhibiting inflammation [PMID:16765572, PMID:16713220, PMID:29421814, PMID:17704976]. It exhibits antioxidant and radical-scavenging properties [PMID:16777393, PMID:16713223]. Pharmacologically, it inhibits the binding of 5-HT(4) and M(3) receptors and opioid receptors [PMID:16973340], and induces a dose-dependent increase in ion secretion in the human intestine [PMID:19210628].

Clinical evidence

Evidence AFunctional Dyspepsia (FD)

STW 5 was found to be more effective than placebo in reducing the severity of the most bothersome gastrointestinal symptoms [PMID:15606389]. STW 5-II significantly improves total symptom sum scores and key symptoms (fullness, early satiety, epigastric pain) [PMID:38246134] and accelerates gastric gas evacuation [PMID:40684457].

Evidence CIrritable Bowel Syndrome (IBS)

STW 5 is documented as an effective therapeutic option for managing IBS symptoms [PMID:29421817, PMID:23263639].

Evidence DFunctional Gastrointestinal Disorders in Children

A prospective observational study of 980 children (age 3-14) evaluated the effectivity and safety of STW 5 under real-life conditions [PMID:35998755].

Safety & adverse effects

The incidence of adverse drug reactions in some reviews was reported at 0.04% [PMID:23263639]. However, a case report documented a 32-year-old female who developed acute severe hepatitis (acute liver injury) characterized by jaundice and pruritus after using Iberogast [PMID:39132058].

Evidence summary

Evidence for the treatment of functional dyspepsia is strong, supported by meta-analyses and RCTs. Evidence for IBS is primarily based on reviews and clinical experience. Safety is generally high, though rare severe hepatic adverse events have been reported.

PubMed sources

1.PMID: 29421817 (2017) — STW 5 (Iberogast) Therapy in Gastrointestinal Functional Disorders. · Digestive diseases (Basel, Switzerland)
2.PMID: 40684457 (2025) — Effect of STW 5-II (Iberogast-N) on Tolerance to Gastric Gas in Patients With Functional Dyspepsia. The IBO-2 Study. · Neurogastroenterology and motility
3.PMID: 23263639 (2013) — STW 5 (Iberogast®)--a safe and effective standard in the treatment of functional gastrointestinal disorders. · Wiener medizinische Wochenschrift (1946)
4.PMID: 39132058 (2022) — Iberogast®-Induced Acute Liver Injury-A Case Report. · Gastro hep advances
5.PMID: 29421793 (2017) — Phytotherapy in Functional Gastrointestinal Disorders. · Digestive diseases (Basel, Switzerland)

Iberogast Formula

Sources & Citations

Calculate a safe dose of Iberogast Formula

Mentha Spicata Var

Fo Shou

Cardamom Seeds

Frequently asked questions

Summary

Background

Active compounds

Mechanism of action

Clinical evidence

Safety & adverse effects

Evidence summary

PubMed sources

Government sources

Iberogast Formula

Sources & Citations

Calculate a safe dose of Iberogast Formula

Related Herbs

Mentha Spicata Var

Fo Shou

Cardamom Seeds

Frequently asked questions

Summary

Background

Active compounds

Mechanism of action

Clinical evidence

Safety & adverse effects

Evidence summary

PubMed sources

Government sources