Herbal formula
Iberogast (STW 5)
Also known as Iberogast Classic, Iberogast Advance, Iberogast N, STW 5, STW 5-II
German herbal drops for indigestion and IBS. Classic has nine herbs including greater celandine; Advance has six and no celandine.
Main use: Indigestion and IBS
Promising clinical evidence
9 ingredients
Updated October 10, 2026
Key points
-
01
Two versions, different herbs
Iberogast Classic (STW 5) has nine herbal extracts, including greater celandine. Iberogast Advance (STW 5-II) has six, without celandine, angelica, or milk thistle.
-
02
Modest benefit for indigestion
Placebo-controlled trials favor both versions for functional dyspepsia, but differences were modest, and a 2023 Cochrane review rated the STW 5 evidence very low certainty.
-
03
One positive IBS trial
In 208 people with IBS, both versions beat placebo over four weeks, while bitter candytuft alone did not. Long-term use has not been studied.
-
04
Research mostly backed by the maker
The newest trial and pooled analysis were funded by Steigerwald, the manufacturer, now owned by Bayer, and a current company employee co-authored several earlier trials.
-
05
Liver warning applies to Classic
Classic is ruled out in liver disease, pregnancy, and breastfeeding after reports of liver failure. Both versions contain 240 mg of alcohol per 20 drops.
Iberogast is a German herbal medicine for the stomach and bowel, sold as bitter brown drops taken in a little liquid before or with meals. In research it is called STW 5. Iberogast Classic, the original version, combines alcohol extracts of nine plants: bitter candytuft, angelica root, chamomile flower, caraway fruit, milk thistle fruit, lemon balm leaf, peppermint leaf, greater celandine herb, and licorice root. Iberogast Advance, tested in research as STW 5-II, keeps six of them and leaves out angelica, milk thistle, and greater celandine. In Germany both are licensed herbal medicines. Classic is approved for functional and motility-related stomach and bowel disorders such as functional dyspepsia (recurring indigestion with no visible cause) and irritable bowel syndrome (IBS), and as supportive treatment of gastritis symptoms; Advance is approved for functional dyspepsia and IBS. Both are made by Steigerwald Arzneimittelwerk in Darmstadt and marketed by Bayer Vital. In the United States, Bayer sells a six-herb Iberogast as a dietary supplement.
Iberogast is an old product by the standards of modern medicines; a 2025 review by Lambiase and colleagues (Expert Opinion on Pharmacotherapy) describes it as available for more than five decades. It was developed by Steigerwald, a family-owned company that Bayer agreed to buy in May 2013, a deal Bayer announced as including the Iberogast brand. By 2001 the company was testing variations of the formula. A 60-patient trial by Madisch and colleagues (Zeitschrift für Gastroenterologie 2001) compared the full product with a version lacking bitter candytuft, and from 2002 trials compared it with STW 5-II, a six-herb research preparation that was later brought to market. Its six herbs match Iberogast Advance, and a 2025 Spanish study called it Iberogast N. The celandine in the nine-herb formula later shaped its regulatory history. Germany’s Federal Institute for Drugs and Medical Devices (BfArM) restricted oral celandine medicines in 2008, pressed Bayer to add liver warnings to Iberogast in September 2018, and the European Medicines Agency (EMA) extended similar warnings across the European Union (EU) in 2021.
Functional dyspepsia and IBS have no single cause, and the rationale for a multi-herb product is that different extracts act on different targets. Reviewers credit it with effects on gut movement, gut sensitivity, inflammation, and the gut lining, drawing largely on laboratory studies (Lambiase and colleagues 2025), and Bayer’s US website says the product helps regulate stomach muscles, calm gut nerves, and reduce stomach acid. None of these mechanisms has been confirmed in people, and no trial has shown which herbs carry the clinical effect. This page sets out what is in each version, what the trials of the combination show and who paid for them, how it is labeled to be taken, and how to use it safely, especially the liver warning attached to the celandine-containing Classic. Results described here belong to the products, not to their individual herbs. Nothing here is medical advice. Ongoing stomach or bowel symptoms deserve a diagnosis before any remedy.
02 The blend
What’s in it
Ingredients in label order. Results from trials of this formula belong to the combination, not to any single herb in it.
-
Bitter candytuft · Whole fresh plant
15.0 ml extract per 100 ml (1:1.5–2.5)
Iberis amara
The lead herb, extracted fresh with 50% ethanol. Also in Advance at the same 15.0 ml. Tested on its own in a 208-patient IBS trial, it did not beat placebo, while both combinations did.
Read the bitter candytuft monograph →
-
Angelica · Root
10.0 ml extract per 100 ml (1:2.5–3.5)
Angelica archangelica
Not in Advance. The root contains furocoumarins, compounds that can make skin more sensitive to sunlight at high exposure. No human trial has separated its contribution from the other herbs.
Read the angelica monograph →
-
Chamomile · Flower
20.0 ml extract per 100 ml (1:2–4)
Matricaria chamomilla
The largest share of Classic and also in Advance, at 30.0 ml per 100 ml. A daisy-family plant, so people allergic to chamomile or its relatives should avoid both versions.
Read the chamomile monograph →
-
Caraway · Fruit
10.0 ml extract per 100 ml (1:2.5–3.5)
Carum carvi
EMA accepts caraway fruit as a traditional remedy for bloating and wind. Also in Advance, at 20.0 ml per 100 ml. EMA rules it out with allergy to carrot-family plants, mugwort, or birch.
Read the caraway monograph →
-
Milk thistle · Fruit
10.0 ml extract per 100 ml (1:2.5–3.5)
Silybum marianum
Not in Advance. Best known for liver research, but its presence has not spared Classic from liver warnings. A daisy-family plant, relevant for people with that allergy.
Read the milk thistle monograph →
-
Lemon balm · Leaf
10.0 ml extract per 100 ml (1:2.5–3.5)
Melissa officinalis
EMA accepts lemon balm leaf as a traditional remedy for mild digestive complaints such as bloating, and for mild stress and sleep. Also in Advance, at 15.0 ml per 100 ml.
Read the lemon balm monograph →
-
Peppermint · Leaf
5.0 ml extract per 100 ml (1:2.5–3.5)
Mentha × piperita
A leaf extract, not the enteric-coated peppermint oil capsules tested for IBS, so those results do not transfer. Also in Advance, at 10.0 ml per 100 ml.
Read the peppermint monograph →
-
Greater celandine · Herb
10.0 ml extract per 100 ml (1:2.5–3.5)
Chelidonium majus
Not in Advance or the US supplement. Germany’s regulator acted on Classic under its procedure for celandine medicines, and Classic now carries liver warnings and is ruled out in liver disease and pregnancy.
Read the greater celandine monograph →
-
Licorice · Root
10.0 ml extract per 100 ml (1:2.5–3.5)
Glycyrrhiza glabra
Also in Advance at the same 10.0 ml. The leaflets do not state the glycyrrhizin content, the compound that in larger amounts raises blood pressure and lowers potassium.
Read the licorice monograph →
03 Evidence
What the research shows
Our rating for indigestion and ibs, based on trials of this combination.
Most of the evidence concerns functional dyspepsia. Melzer and colleagues (Alimentary Pharmacology and Therapeutics 2004) found six randomized trials of STW 5, partly by consulting the manufacturer, and pooled the raw data of the three placebo-controlled ones: 138 people on the drops did better than 135 on placebo on their most bothersome symptom (odds ratio 0.22, 95% confidence interval 0.11–0.47), with similar side effects and no serious events. The largest single trial, by von Arnim and colleagues (American Journal of Gastroenterology 2007), gave 315 patients who had been examined by endoscopy 20 drops three times a day or placebo for eight weeks. A validated symptom score improved by 6.9 points with STW 5 and 5.9 with placebo, a statistically significant but small difference because placebo also helped a lot. In an active-comparator trial, Rösch and colleagues (Zeitschrift für Gastroenterologie 2002) randomized 186 patients to STW 5, STW 5-II, or the prokinetic drug cisapride for four weeks; both herbal versions met the test for non-inferiority, with 137 patients in the confirmatory analysis.
The six-herb STW 5-II has its own placebo-controlled trials. Madisch and colleagues (Digestion 2004) randomized 120 people with functional dyspepsia and found a significantly greater fall in symptom scores than with placebo during the first four weeks. In the largest trial, Vinson and colleagues (JGH Open 2024) treated 272 patients for eight weeks: 61.2% responded on STW 5-II against 45.1% on placebo, but the average symptom score improvement narrowly missed significance (7.9 versus 6.7 points, p = 0.07). Andresen and colleagues (Digestion 2024) identified four randomized trials with 613 patients, pooled two for efficacy, and reported improvements in total symptoms and in fullness, early satiety, and upper abdominal pain at four and eight weeks, with no difference from placebo in treatment-related or severe side effects. Funding matters here. The Vinson trial was funded by Steigerwald and two of its authors are company employees; Steigerwald also funded the Andresen analysis and helped design and write it. The abstracts of the older trials do not state who paid, but Bettina Vinson, listed as a Steigerwald employee in the 2024 trial, co-authored several of them.
For IBS there is one main trial. Madisch, Holtmann, Plein, and Hotz (Alimentary Pharmacology and Therapeutics 2004) assigned 208 patients, after a standardized diagnostic work-up, to STW 5 (51), STW 5-II (52), a bitter candytuft single-herb extract (53), or placebo (52) for four weeks, and 203 finished. Both combinations reduced abdominal pain and IBS symptom scores significantly more than placebo, while the bitter candytuft extract did not (p = 0.15 and p = 0.12). That result is one reason single-herb findings cannot be borrowed for this product, or product findings credited to a single herb. Another is that the ingredients are not the forms studied elsewhere: the peppermint in Iberogast is a leaf extract, not the enteric-coated peppermint oil capsules recommended for IBS, and the caraway is a fruit extract, not caraway oil. The Advance leaflet states that efficacy rests on one four-week IBS trial and one eight-week dyspepsia trial, and that repeat courses and long-term treatment have not been studied.
Independent reviewers are more cautious than the trial authors. Báez and colleagues’ 2023 Cochrane review of non-Chinese herbal medicines for functional dyspepsia found that STW 5 may moderately improve global symptoms compared with placebo at 28 to 56 days (mean difference −2.64 points; five trials, 814 participants), but rated the evidence very low certainty because results varied widely between trials. A possible increase in the proportion of people who improved was rated low certainty, as was the finding of little or no difference in side effects (risk ratio 0.92; four trials, 786 participants). Germany’s 2026 guideline on functional dyspepsia from the German Society for Neurogastroenterology and Motility (Storr and colleagues) takes a more favorable view: it counts STW 5, STW 5-II, and peppermint oil with caraway oil as first-line therapies, while describing the supporting trials as various small randomized trials, mostly from German-speaking countries. Several guideline authors reported lecture or advisory fees from Bayer Vital or research support from Steigerwald.
Regulatory status differs by country. In Germany, Classic is a nationally licensed, pharmacy-only medicine (authorization number 6463148.00.00), and Advance is also licensed as a herbal medicine. EMA has not written a European herbal monograph for the combination, but its Pharmacovigilance Risk Assessment Committee (PRAC) reviewed the nine-herb product’s safety reports in 2021, as described under safety. In the United States, Bayer sells Iberogast as a dietary supplement for occasional upset stomach, gas, bloating, and similar complaints. The US Food and Drug Administration (FDA) does not approve dietary supplements before they are sold. Bayer’s US site lists the same six herbs as Advance but does not publish their amounts, so whether it matches the tested STW 5-II is not stated, and no trials of its softgel or gummy forms were found. Open questions include long-term and repeat use, how STW 5 compares directly with established drugs, which Lambiase and colleagues list as a research priority, and how well the mainly German trial results apply elsewhere.
04 In practice
How it is taken
In Germany both versions come as dark brown liquids in glass dropper bottles of 20, 50, or 100 ml. The leaflets describe a green cap for Classic and a purple cap for Advance, which is the quickest way to tell them apart, since only Classic contains greater celandine. Each is an alcohol extract: per 100 ml, the bitter candytuft extract is made with 50% ethanol and the others with 30% ethanol, and each 20-drop dose contains 240 mg of alcohol. In the United States, Bayer sells a six-herb Iberogast as liquid drops, softgels, and elderberry-flavored gummies, labeled for adults 18 and older. The published trials tested the German liquid preparations. Other products sold in other countries under the Iberogast name may differ, so read the ingredient list and check for greater celandine (Chelidonium majus, Schöllkraut) before choosing.
The adult dose matches the 20 drops three times a day used in the largest STW 5 trial. Adults and adolescents from 13 take 20 drops of Classic three times a day before or with meals in a little liquid; children aged 6 to 12 take 15 drops and children aged 3 to 5 take 10 drops. Advance is 20 drops three times a day for adults and adolescents from 12, preferably in water, and is not recommended under 12. Both bottles should be shaken before use and held at a 45-degree angle when counting drops. The US drops are labeled at 20 drops in a drink three times a day, and the softgels and gummies at one unit three times a day. The Classic leaflet sets no fixed time limit and says the duration depends on the type, severity, and course of the condition. The Advance leaflet notes that its trials lasted four weeks for IBS and eight weeks for dyspepsia, and that long-term use has not been studied. An opened Classic bottle keeps for eight weeks; an opened Advance bottle keeps for four weeks (20 and 50 ml) or eight weeks (100 ml).
Both German leaflets give the same advice on when to see a doctor: if symptoms have not improved after one week of first use, to rule out another cause, and whenever symptoms worsen or new ones appear. The Classic leaflet adds that children under 6 with abdominal pain should always see a doctor. The Advance leaflet says children under 12 with functional stomach or bowel symptoms should see a doctor, and that in adolescents aged 12 to 18 such symptoms can have psychological causes or point to an eating disorder. Stop either product at once and seek advice for any sign of an allergic reaction, and stop Classic immediately for any sign of liver trouble. When choosing, the main question is whether the celandine-containing Classic is appropriate at all: anyone with a past or current liver problem, anyone taking medicines with liver warnings, and anyone pregnant or breastfeeding is excluded by its label. Avoid taking it alongside other products containing licorice or celandine.
05 Caution
Before you use Iberogast (STW 5)
In trials, side effects were about as common as on placebo. Melzer and colleagues found similar adverse events with STW 5 and placebo and no serious ones, Cochrane found little or no difference (low certainty), and Andresen and colleagues found no difference in treatment-related or severe events with STW 5-II. Both leaflets list allergic reactions such as rash, itching, and breathing difficulty; Classic rates them very rare (fewer than 1 in 10,000 people). Liver injury is the serious concern, and it is tied to Classic. Its leaflet lists liver damage of unknown frequency, from raised liver enzymes to jaundice, hepatitis, and liver failure. In 2018 BfArM reported a second case of liver failure with transplantation after Iberogast use, which ended in death. Published case reports describe liver toxicity leading to transplantation (Sáez-González and colleagues 2016), acute liver failure in which re-exposure and a laboratory test supported a causal link (Gerhardt and colleagues 2019), and severe hepatitis in a 32-year-old woman that resolved five weeks after stopping (Leroy and colleagues 2022). In 2021 PRAC judged a causal link between Iberogast and drug-induced liver injury at least a reasonable possibility.
Iberogast Classic must not be taken by anyone who has or has had liver disease, with medicines whose leaflets list liver damage as a side effect, in pregnancy or while breastfeeding, by children under 3, or by anyone allergic to its ingredients. Advance lists only allergy as a contraindication and is not recommended under 12. For pregnancy and breastfeeding its leaflet says the available data raise no concern but that it should be taken only after talking to a doctor; note that EMA’s 2026 licorice monograph does not recommend licorice root medicines in pregnancy or breastfeeding, and the leaflets do not state how much glycyrrhizin Iberogast supplies. The US supplement is for adults 18 and older and should not be used in pregnancy or breastfeeding, according to Bayer. Chamomile, and in Classic milk thistle, belong to the daisy family, so people allergic to those plants should avoid the products. Each 20-drop dose contains 240 mg of alcohol, about 720 mg a day at the full adult dose; the leaflets compare one dose with less than 7 ml of beer, which still matters for people who avoid alcohol entirely.
Interactions: Classic must not be combined with medicines whose leaflets list liver damage as a side effect, a rule EMA extended across the EU in 2021; the same logic applies to other products containing greater celandine and to herbs with liver warnings of their own. Otherwise the Classic leaflet states that no interactions are known, and the Advance leaflet that none emerged in its trials, which is not proof that none exist. Licorice, in both versions, is the ingredient with the clearest interaction profile. EMA’s 2026 licorice monograph says licorice root may counteract blood pressure medicines, should not be combined with diuretics, digoxin-type heart drugs, corticosteroids, or stimulant laxatives, calls for caution with drugs broken down by the liver enzyme CYP3A4, and warns against taking more than one licorice product at once. Angelica root in Classic contains furocoumarins that can sensitize skin to sunlight, though EMA’s herbal committee identified exposure levels below which this is not considered relevant. No interactions are listed for bitter candytuft, chamomile, caraway, milk thistle, lemon balm, or peppermint in these leaflets, and none has been studied with the combination.
Stop Classic immediately and see a doctor for yellowing of the skin or eyes, dark urine, pale stools, or pain in the upper abdomen; BfArM’s required wording adds nausea, loss of appetite, and tiredness as possible signs of liver damage. Breathing difficulty after a dose needs urgent care. Indigestion and bowel symptoms also need a doctor rather than a remedy when alarm features are present. The 2026 German guideline lists new symptoms after about age 55, a family history of stomach cancer, weight loss, anemia, vomiting, difficulty swallowing, bleeding from the upper gut (such as vomiting blood or black stools), fever, and a lump in the abdomen. Both leaflets add that symptoms which worsen or change while taking the drops need a doctor. Functional dyspepsia and IBS are diagnoses made after other causes have been considered, and a herbal product can mask the symptoms of a condition that needs treatment.
06 Questions
Frequently Asked Questions
Iberogast Classic contains extracts of nine plants: bitter candytuft (the whole fresh plant), angelica root, chamomile flower, caraway fruit, milk thistle fruit, lemon balm leaf, peppermint leaf, greater celandine, and licorice root. Iberogast Advance keeps bitter candytuft, chamomile, caraway, lemon balm, peppermint, and licorice, with larger shares of most of them, and drops the other three. Both are alcohol extracts with 240 mg of alcohol in each 20-drop dose.
For functional dyspepsia, probably modestly. Three pooled placebo-controlled trials (273 people) favored STW 5, and an eight-week trial of 315 patients found a small but significant advantage. A 2023 Cochrane review agreed it may help but rated the evidence very low certainty because results varied so much. For IBS, one 208-patient trial found both versions better than placebo over four weeks. Most trials were funded by or involved the manufacturer, and long-term use has not been studied.
Classic (STW 5) has nine herbal extracts, including greater celandine, angelica, and milk thistle; Advance (STW 5-II) has six and none of those three. Classic carries liver warnings and must not be used with liver disease, in pregnancy, or while breastfeeding, while Advance lists only allergy as a contraindication. Classic is labeled from age 3 and Advance from 12. In Germany, Classic has a green cap and Advance a purple one.
Iberogast Classic has been linked to liver injury, including liver failure with transplantation and a death reported in Germany in 2018, and in 2021 the European Medicines Agency’s safety committee judged a causal link at least a reasonable possibility. Regulators acted under their rules for greater celandine, which Classic contains. Advance lists no liver reactions. On any version, stop and see a doctor for yellow skin or eyes, dark urine, pale stools, or upper abdominal pain.
Not exactly. In the US, Bayer sells Iberogast as a dietary supplement rather than a licensed medicine, as drops, softgels, and gummies. It lists six herbs, the same ones as Iberogast Advance, and no greater celandine, but the website does not give the amounts. It is labeled for adults 18 and older and not for use in pregnancy or breastfeeding. The clinical trials tested the German liquid preparations, not the softgels or gummies.
Iberogast Classic must not be used in pregnancy or while breastfeeding and is not for children under 3; children aged 3 to 12 take smaller labeled doses, and under-6s with tummy pain should always see a doctor. Advance is not recommended under 12, and its leaflet says to use it in pregnancy or breastfeeding only after talking to a doctor. Both contain alcohol and licorice, which Europe’s herbal committee does not recommend in pregnancy, so ask a doctor or midwife first.
Each 20-drop dose of Classic or Advance contains 240 mg of alcohol (ethanol), or about 720 mg a day at the usual adult dose of three times 20 drops. The German leaflets compare one dose with less than 7 ml of beer or 3 ml of wine and say it has no noticeable effects. Bayer’s US site confirms that its drops also contain alcohol but does not give the amount. People who avoid alcohol completely should take this into account.
They have been tested for different uses and not against each other. Peppermint oil capsules are the best-supported herbal option for IBS. For functional dyspepsia, Cochrane rated peppermint and caraway oil capsules as probably giving a large improvement (moderate certainty), against very low certainty for STW 5, and Germany’s 2026 guideline lists both as first-line options. We found no trial comparing them directly.
07 References
Sources
These references support the claims on this page. They are not an endorsement of any product. Each ingredient’s monograph carries its own full source list.
-
Iberogast® Produkte Pflichttexte für Endverbrauchende
Bayer Vital GmbH, 2023
Mandatory texts (status 09/2023): composition per 100 ml of Classic (nine extracts) and Advance (six), indications, contraindications, liver damage for Classic, allergy frequencies, and 240 mg ethanol per 20 drops.
-
Gebrauchsinformation: Iberogast® Classic
Bayer Vital GmbH, via PatientenInfo-Service, 2023
Classic leaflet: label order of ingredients, doses by age from 3, see a doctor after one week, liver warning signs, no interactions known, not in pregnancy or breastfeeding, green cap, 8-week shelf life, made by Steigerwald.
-
Gebrauchsinformation: Iberogast® ADVANCE
Bayer Vital GmbH, via PatientenInfo-Service, 2023
Advance leaflet: 20 drops three times daily from 12; not recommended under 12; pregnancy only after consulting a doctor; 4-week IBS and 8-week dyspepsia trials; repeat and long-term use not studied; purple cap.
-
Iberogast FAQ
Bayer (United States), 2026
US Iberogast is a dietary supplement with a six-herb blend (Iberis amara, peppermint, German chamomile, licorice, lemon balm, caraway) as drops, softgels, and gummies; adults 18 and older; not in pregnancy or breastfeeding; contains alcohol.
-
Questions and Answers on Dietary Supplements
US Food and Drug Administration, 2026
Supports the statement that FDA does not approve dietary supplements or their labeling before they are marketed.
-
Strategic move to strengthen Consumer Care business: Bayer to acquire Steigerwald Arzneimittelwerk GmbH
Bayer HealthCare, via PR Newswire, 2013
May 16, 2013: Bayer agreed to acquire the family-owned Darmstadt company Steigerwald, including the Iberogast brand.
-
Meta-analysis: phytotherapy of functional dyspepsia with the herbal drug preparation STW 5 (Iberogast)
Alimentary Pharmacology and Therapeutics (PubMed 15606389), 2004
Melzer et al.: six RCTs identified, partly via the producer; three placebo-controlled trials pooled (138 vs 135); odds ratio 0.22 (95% CI 0.11–0.47); no difference from cisapride; adverse events similar to placebo.
-
STW 5, a phytopharmacon for patients with functional dyspepsia: results of a multicenter, placebo-controlled double-blind study
American Journal of Gastroenterology (PubMed 17531013), 2007
Von Arnim et al.: 315 patients (158 STW 5, 157 placebo), 20 drops three times daily for 8 weeks; symptom score improved 6.9 vs 5.9 points (P<0.05); tolerability similar.
-
Treatment of irritable bowel syndrome with herbal preparations: results of a double-blind, randomized, placebo-controlled, multi-centre trial
Alimentary Pharmacology and Therapeutics (PubMed 14984373), 2004
Madisch et al.: 208 IBS patients in four arms; STW 5 and STW 5-II beat placebo on abdominal pain and IBS symptom scores at 4 weeks; bitter candytuft mono-extract did not (P = 0.1473 and 0.1207).
-
Double-blind, randomized, 8-week multicenter study of the efficacy and safety of STW 5-II versus placebo in functional dyspepsia
JGH Open (PubMed 38699471), 2024
Vinson et al.: 272 patients; response 61.2% vs 45.1% (P = 0.008); mean score change 7.9 vs 6.7 (P = 0.07); funded by Steigerwald, two authors company employees.
-
Efficacy and Safety of STW 5-II for Functional Dyspepsia Treatment: A Patient Data-Based Meta-Analysis
Digestion (PubMed 38246134), 2024
Andresen et al.: four RCTs (613 patients), two pooled for efficacy; improvements in total and key symptoms at 4 and 8 weeks; no difference in treatment-related or severe adverse events; funded and co-written by Steigerwald.
-
Non-Chinese herbal medicines for functional dyspepsia
Cochrane Database of Systematic Reviews (PubMed 37323050), 2023
Báez et al.: STW 5 vs placebo MD −2.64 (5 trials, 814 participants; very low certainty); improvement rate RR 1.55 (low); adverse events RR 0.92 (low); peppermint and caraway oil moderate certainty.
-
S1 Guideline of the German Society for Neurogastroenterology and Motility (DGNM) on Functional Dyspepsia (FD), a Disorder of Gut-Brain Interaction (DGBI) [English Language Edition]
Gastroenterology Research and Practice (PubMed 42095009), 2026
Storr et al.: STW 5/STW 5-II and peppermint oil with caraway oil considered first-line therapies; evidence from various small RCTs; alarm symptoms listed; several authors disclose Bayer Vital or Steigerwald ties.
-
Schöllkrauthaltige Arzneimittel zur innerlichen Anwendung
Bundesinstitut für Arzneimittel und Medizinprodukte (BfArM), 2018
April 2008 restrictions on oral celandine medicines; September 2018 liver warnings, liver-disease contraindication, and pregnancy and breastfeeding contraindication for Iberogast after a second, fatal case of liver failure with transplantation.
-
Scientific conclusions and grounds for the variation to the terms of the marketing authorisation(s): ethanol extracts of Iberis amara and eight other herbs (PSUSA/00010800/202011)
European Medicines Agency, PRAC and CMDh, 2021
PRAC judged a causal relationship between Iberogast and drug-induced liver injury at least a reasonable possibility; EU-wide liver contraindication and warning signs adopted July 2021.
-
European Union herbal monograph on Glycyrrhiza glabra L.; Glycyrrhiza inflata Bat.; Glycyrrhiza uralensis Fisch., radix (Revision 1)
European Medicines Agency (EMA/HMPC/108399/2024), 2026
Licorice root not recommended in pregnancy or breastfeeding; may counteract antihypertensives; not with diuretics, cardiac glycosides, corticosteroids, or stimulant laxatives; caution with CYP3A4 substrates; avoid combining licorice products.