Herbal formula

Peppermint and Caraway Oil

Q: What is peppermint and caraway oil?

It is a fixed combination of two essential oils in an enteric-coated capsule: 90 mg of peppermint oil and 50 mg of caraway oil per capsule in Menthacarin, made by Schwabe and sold as Carmenthin in Germany and Belgium, Gaspan in Austria, Slovakia, and the Czech Republic, and Gastropan in Spain. Its early trials used the name Enteroplant. In Germany it is licensed for indigestion with mild cramps, bloating, and fullness.

Q: Does it work for indigestion?

For functional dyspepsia, probably, for some people. Three placebo-controlled trials with 249 patients found less upper-abdominal pain and more global improvement after four weeks, and a 2023 Cochrane review rated the evidence for global symptom improvement as moderate certainty. The trials were small, mostly run with the manufacturer, and none compared the capsule with acid-reducing drugs. Get persistent or new indigestion checked before treating it yourself.

Q: Does peppermint and caraway oil help IBS?

That is not proven. A 200-patient placebo-controlled IBS trial, published only as a congress abstract, found improvement without a statistically significant difference from placebo. Analyses of dyspepsia patients with IBS-type symptoms and an uncontrolled 2026 study were positive but cannot show cause and effect. For IBS itself, enteric-coated peppermint oil alone has much stronger evidence.

Q: Is FDgard the same as Menthacarin?

No. FDgard, a US dietary supplement, contains caraway oil and L-menthol, the key active compound of peppermint oil, rather than whole peppermint oil; its label lists the menthol as coming from corn mint (Mentha arvensis). A two-capsule serving holds 50 mg caraway oil and 41.5 mg L-menthol in coated microspheres. Its 95-patient trial did not beat placebo on the overall symptom score, though some secondary results favored it. Results for one product do not transfer to the other.

Q: How do I take it, and for how long?

Following the German label, adults and adolescents from 12 take one capsule twice a day, swallowed whole with water at least 30 minutes before a meal, ideally morning and midday. Do not chew it. Most trials lasted four weeks. See a doctor if symptoms last more than a week or keep returning (German label), or persist after two weeks (Austrian leaflet). FDgard is dosed differently: two capsules twice a day, 30 to 60 minutes before meals.

Q: Can I take it with omeprazole or antacids?

Only with careful timing. Antacids, H2 blockers, and proton pump inhibitors such as omeprazole can make the enteric coating dissolve in the stomach, causing minty burping and irritation. The German label advises keeping antacids at least an hour apart and not taking the capsule one to three hours after a PPI; the Austrian leaflet says to take the capsule at least two hours before an acid reducer when both are needed. A pharmacist can help plan the timing.

Q: Who should not take it?

Avoid it with gallstones, bile duct inflammation or other biliary disease, liver disease, no stomach acid (achlorhydria), or an allergy to peppermint, menthol, caraway, or carrot-family plants; in volunteers, each oil completely blocked gallbladder emptying. It is not recommended in pregnancy or while breastfeeding and is labeled for ages 12 and up. People with reflux or a hiatal hernia may find heartburn gets worse and should stop if it does.

Q: How does it compare with Iberogast?

Iberogast (STW 5) is a liquid German multi-herb formula that is also used for functional dyspepsia. In the 2023 Cochrane review, its evidence for improving global dyspepsia symptoms was rated very low certainty, while peppermint and caraway oil was rated moderate certainty. Each product’s results belong to that product, so neither can stand in for the other.

Also known as Menthacarin, Carmenthin, Enteroplant, Gaspan, Gastropan, peppermint oil and caraway oil capsules, PCC, POCO

Enteric-coated capsules of peppermint and caraway oil, studied mainly by their maker for functional dyspepsia (chronic indigestion).

Main use: Functional dyspepsia (indigestion)

Promising clinical evidence

2 ingredients

Updated October 10, 2026

Key points

01

Two oils in one coated capsule

Menthacarin pairs 90 mg peppermint oil with 50 mg caraway oil in an enteric-coated capsule, sold as Carmenthin in Germany and Gaspan in Austria.
02

Best studied for functional dyspepsia

Three placebo-controlled trials with 249 patients found less upper-abdominal pain after four weeks. A 2023 Cochrane review rated the evidence moderate certainty.
03

Research led by the manufacturer

Schwabe funded the largest placebo trial and the 2023 meta-analysis, and company scientists co-wrote both. Independent replication remains limited, and IBS benefit is unproven.
04

FDgard is a different product

The US supplement FDgard pairs caraway oil with isolated L-menthol, not whole peppermint oil, in coated microspheres. Its 95-patient trial missed the overall symptom score.
05

Gallbladder, liver, and antacid cautions

Avoid with gallstones, bile duct or liver disease, or no stomach acid. Antacids, H2 blockers, and PPIs can dissolve the coating early, causing minty burping.

Peppermint and caraway oil is a fixed combination of two essential oils in one enteric-coated capsule, made to ease chronic indigestion. Its best-known form, Menthacarin, comes from the German company Dr. Willmar Schwabe: each soft capsule holds 90 mg of peppermint oil and 50 mg of caraway oil, according to the German prescribing information (Fachinformation) for Carmenthin bei Verdauungsstörungen, last updated in October 2024. The Austrian package leaflet (March 2025) lists the same 90 mg/50 mg product as Gaspan in Austria, Slovakia, and the Czech Republic, Carmenthin in Belgium, and Gastropan in Spain, and the early trials used the brand name Enteroplant. In Germany it is a licensed, pharmacy-only medicine for dyspeptic complaints, especially with mild cramps in the stomach and gut, bloating, and a feeling of fullness. In the United States, a related but different product, FDgard, combines caraway oil with L-menthol, a single compound, rather than whole peppermint oil, and is sold as a dietary supplement.

Both ingredients have long histories as digestive remedies. The European Medicines Agency (EMA) accepts caraway oil as a traditional herbal medicine for bloating and flatulence, “exclusively based upon long-standing use,” and accepts enteric-coated peppermint oil on clinical evidence for cramping, wind, and abdominal pain, especially in irritable bowel syndrome (IBS). Combining the two in a capsule designed to pass the stomach intact was tested in Germany from the 1990s. May and colleagues published the first placebo-controlled trial of the combination, then called Enteroplant, in Arzneimittelforschung in 1996 and a second in 2000, and Madisch and colleagues compared it with the prescription drug cisapride in 1999. Germany granted the current marketing authorization in 2002 and renewed it in 2014. Recent papers call the active ingredient Menthacarin, a proprietary pairing of Schwabe’s peppermint oil WS 1340 and caraway oil WS 1520 (Madisch and colleagues, Digestive Diseases 2023). FDgard was developed separately in the United States, where its 2019 trial was funded by IM HealthScience; its label now names Nestlé HealthCare Nutrition.

How the capsule works is only partly understood. In a manufacturer-funded review, Madisch and colleagues summarize laboratory findings that both oils relax muscle from surgically removed human intestine by blocking L-type calcium channels, that peppermint oil activates TRPM8, the cold-sensing receptor on nerves, and that in a rat model of gut pain after inflammation the combination reduced pain sensitivity while neither oil did on its own. The German prescribing information reports that one capsule dampened movement of the duodenum in volunteers. The coating delays release, so the effect may begin only after 1 to 1½ hours, and the half-lives of menthol and carvone, the main compounds of the two oils, are about 3.5 and 2.5 hours. This page covers what is in the capsule, what trials of this exact product found, how it is taken, and who should avoid it, including the gallbladder warning both oils share. Nothing here is medical advice.

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.

Peppermint · Essential oil

90 mg per capsule (Carmenthin, Gaspan)

Mentha × piperita

Schwabe’s peppermint oil WS 1340. Its main component, menthol, acts on TRPM8, the cold-sensing receptor, and the oil relaxes gut muscle in lab studies. Same plant and oil as the peppermint monograph, but this dose is tested only in the combination.

Read the peppermint monograph →
Caraway · Essential oil

50 mg per capsule (Carmenthin, Gaspan)

Carum carvi

Schwabe’s caraway oil WS 1520, whose main component is carvone. EMA accepts caraway oil alone only as a traditional remedy for bloating. On its own, 50 mg blocked gallbladder emptying in volunteers, the basis for the biliary warnings.

Read the caraway monograph →

03 Evidence

What the research shows

Promising clinical evidence

Our rating for functional dyspepsia (indigestion), based on trials of this combination.

Three placebo-controlled trials in functional dyspepsia (recurring upper-abdominal pain, fullness, or early satiety without a structural cause) form the core of the evidence. May and colleagues (Arzneimittelforschung 1996) enrolled 45 patients and analyzed 39, giving one capsule three times a day; after four weeks, pain and the investigators’ global rating improved significantly more than with placebo, and 63.2% of the active group were pain-free. Their second trial (Alimentary Pharmacology and Therapeutics 2000) gave 96 outpatients one capsule twice daily or placebo for 28 days: pain fell 40% versus 22%, pressure, heaviness, and fullness 43% versus 22%, and 67% versus 21% were rated much or very much improved, with no peppermint-tasting burps. The largest, by Rich and colleagues (Neurogastroenterology and Motility 2017), randomized 114 outpatients for four weeks; on the Nepean Dyspepsia Index, pain scores improved by 7.6 versus 3.4 points and discomfort by 3.6 versus 1.3 (P < .001), in both the pain-predominant and the meal-related forms of dyspepsia. Schwabe is listed as that trial’s funder, and three authors worked in its clinical research department. The abstracts of the earlier trials do not state their funding.

Two double-blind trials compared the capsule with active treatments instead of placebo. Against cisapride, a prokinetic drug later withdrawn or restricted in many countries over safety concerns, pain scores in 118 analyzed patients fell 4.62 points with the combination and 4.60 with cisapride over four weeks, meeting the test for equivalence (Madisch and colleagues, Arzneimittelforschung 1999). Freise and Köhler (Pharmazie 1999) found the enteric-coated capsule as effective as an immediate-release version in 213 patients, with fewer peppermint-tasting burps. Pooling the three placebo trials (249 patients), Madisch and colleagues (Digestive Diseases 2023) found a standardized mean difference in pain reduction of 0.80 and a risk ratio of 2.65 for being much or very much improved. Schwabe sponsored that meta-analysis, two authors were its employees, the others had received its honoraria, and a writer paid by the sponsor drafted the first version. The independent 2023 Cochrane review of non-Chinese herbal medicines for functional dyspepsia (Báez and colleagues) concluded that peppermint and caraway oil probably produce a large improvement in global symptoms at four weeks (moderate certainty; risk ratio 1.53 for improvement, three studies, 305 participants), with little or no difference in adverse events (low certainty).

Evidence beyond indigestion is weaker. A placebo-controlled trial in 200 people with IBS, published only as a congress abstract and summarized in the 2023 meta-analysis, found symptoms improved over eight weeks, but the difference from placebo did not reach statistical significance; the authors suggest that people with diarrhea-predominant IBS may benefit most. A pooled re-analysis of 111 dyspepsia patients who also had IBS-type symptoms found larger improvements than with placebo, but a subgroup is not an IBS trial. Uncontrolled studies mostly add tolerability data: an 11-month open follow-up of the 2000 trial, a four-week study of 2,148 primary-care patients in which 0.3% reported adverse events, and a 2026 single-arm trial by Linas and colleagues (Wiener medizinische Wochenschrift) in which 126 people with abdominal pain, cramps, or bloating improved over eight weeks. Without a control group, such studies cannot separate the capsule’s effect from placebo response or natural ups and downs, and the 2026 trial was again funded by Schwabe. The National Center for Complementary and Integrative Health (NCCIH) says peppermint oil plus caraway oil may help indigestion, while peppermint oil taken alone may make it worse.

FDgard’s research is separate and should not be merged with Menthacarin’s. Chey and colleagues (Clinical and Translational Gastroenterology 2019) randomized 95 adults with functional dyspepsia to placebo or two capsules twice a day, each with 25 mg caraway oil and 20.75 mg L-menthol in coated microspheres meant to open in the duodenum, for four weeks; participants could keep taking their usual dyspepsia medicines. For the whole group, the overall symptom score did not differ significantly from placebo at two or four weeks. Fullness and early-satiety symptoms improved more at 24 hours, and among people with more severe symptoms about three-quarters versus half reported substantial global improvement. The trial was funded by IM HealthScience, and several authors were its consultants or staff. A later report from the same group (Lacy and colleagues, BMC Gastroenterology 2022) adds an online survey of 600 users and safety surveillance, which are not controlled evidence.

Regulators treat the combination as a product, not as a herb. EMA has no monograph for peppermint and caraway oil together; Carmenthin, Gaspan, and their sister brands hold national authorizations, and their labels set the doses and cautions. In the United States, FDgard is a dietary supplement, a category the Food and Drug Administration (FDA) does not approve before sale (NCCIH). Single-herb evidence cannot be borrowed in either direction. EMA accepts caraway oil alone only on traditional use, and peppermint oil’s strongest support is for IBS, not indigestion, where NCCIH finds no evidence that it helps alone. The trials tested one specific enteric-coated capsule, and FDgard uses isolated menthol and a different delivery system. Open questions remain: independent replication is limited, most trials lasted four weeks, none compared the capsule with proton pump inhibitors (PPIs), a standard indigestion treatment, and its value in IBS is unproven.

04 In practice

How it is taken

Menthacarin comes only as enteric-coated soft capsules (gastro-resistant, meaning the coating resists stomach acid), each with 90 mg peppermint oil and 50 mg caraway oil. Brand names vary by country: Carmenthin bei Verdauungsstörungen in Germany, Carmenthin in Belgium, Gaspan in Austria, Slovakia, and the Czech Republic, and Gastropan in Spain. In Germany it is sold only in pharmacies but does not need a prescription. FDgard, sold in the United States, is not the same formula: a label in the National Institutes of Health’s supplement label database lists 50 mg caraway oil and 41.5 mg L-menthol per two-capsule serving, with the menthol from Mentha arvensis (corn mint), in coated microspheres inside the capsule. Peppermint oil capsules sold for IBS contain no caraway, and NCCIH finds no evidence that peppermint oil alone helps indigestion. When comparing products, check that the label names both oils, their amounts per capsule, and an enteric or gastro-resistant coating; the published trial results apply only to the product tested.

The German label dose for adults and adolescents from 12 years is one capsule twice a day, swallowed whole with a glass of water at least 30 minutes before a meal, ideally in the morning and at midday; the capsule can also be taken without a meal afterward. Chewing or breaking it releases the oil early and can irritate the mouth and esophagus. Most trials used this dose for four weeks, and the small 1996 trial used one capsule three times a day. FDgard’s label tells adults to take two capsules twice a day, 30 to 60 minutes before meals with water, and no more than six capsules a day; they may be swallowed whole or opened and mixed with a non-dairy food, but not chewed. If a pre-meal dose is missed, FDgard’s label allows taking it with or after a meal. EMA advises against taking other peppermint oil medicines at the same time as a peppermint oil capsule.

Labels differ on how long to continue. The German prescribing information sets no general time limit but recommends seeing a doctor if complaints last longer than one week or keep coming back, because stomach and bowel complaints can be signs of illnesses that need medical assessment. The Austrian Gaspan leaflet says to take the capsules until symptoms settle, usually within two to four weeks, to see a doctor if they persist or worsen after two weeks, and to continue for no longer than three months per course. Longer use rests mainly on an open 11-month follow-up of the 2000 trial, in which 72 of the 96 patients took the capsule and symptoms in both former groups improved and converged (Madisch and colleagues 2023). FDgard’s label says to stop and consult a healthcare provider if symptoms persist or worsen or any adverse reaction occurs. Stop either product if heartburn flares, a rash or swelling appears, or symptoms change.

05 Caution

Before you use Peppermint and Caraway Oil

In trials the capsule was generally well tolerated. The German label lists stomach upset such as burping in sensitive people and, very rarely, allergic reactions; the Austrian leaflet lists heartburn, nausea, burping, burning around the anus, and allergic reactions such as redness, swelling, and itching, all of unknown frequency. Adverse events were few in the 1996 trial (4 with the capsule, 3 with placebo) and the 2000 trial (5 versus 1, described as unrelated to treatment or due to the dyspepsia itself), and the 2023 Cochrane review found little or no difference from placebo (low certainty). Burping that tastes of the oils is the sign that the coating opened too early. People who already have heartburn or a hiatal hernia sometimes find it worse after peppermint oil and should stop (EMA; Austrian leaflet). EMA’s peppermint oil monograph adds menthol-smelling urine and stools and rare menthol allergy. Overdose of essential oils can cause vomiting, abdominal pain, drowsiness, seizures, and breathing problems, and small children are especially vulnerable, so store capsules out of their reach.

Do not use it with an allergy to peppermint, menthol, caraway, or other carrot-family plants, which EMA lists as fennel, anise, celery, coriander, and dill. The German and Austrian labels contraindicate it with gallstones, inflammation of the bile ducts (cholangitis) or other biliary disease, liver disease, and achlorhydria (no stomach acid). The gallbladder warning has a direct basis: in 12 healthy volunteers, 90 mg peppermint oil and 50 mg caraway oil, each given alone, completely blocked gallbladder emptying (Goerg and Spilker, Alimentary Pharmacology and Therapeutics 2003). EMA also advises caution with peppermint oil in inflamed or ulcerated conditions of the gut. Children: Carmenthin and Gaspan are for ages 12 and up, and the Austrian leaflet notes a lack of data from 8 to 11 and forbids use under 8, because pulegone and menthofuran, minor compounds in peppermint oil, could exceed safe limits. FDgard’s label gives adult dosing only. Pregnancy and breastfeeding: the German label does not recommend it in pregnancy and says it should not be used while breastfeeding, and the Austrian leaflet notes that 1,8-cineole from peppermint oil can pass into breast milk.

Acid-reducing medicines are the main practical interaction. Antacids, H2 blockers, and PPIs such as omeprazole can make the coating dissolve in the stomach, causing burping that tastes of the oils and possible stomach irritation. The German label advises taking antacids at least one hour apart from the capsule and not taking the capsule one to three hours after a PPI; the Austrian leaflet says to avoid combining them and, when both are medically needed, to take the capsule at least two hours before the acid reducer. Food taken at the same time can also open the coating early. No interaction studies have been done on the combination itself. EMA notes some inhibition of CYP3A4, a liver enzyme that clears many drugs, in one clinical study with peppermint oil and one with menthol, so people on medicines with a narrow safety margin should check with a pharmacist. EMA lists no interactions for caraway oil, although its 2020 review discussed two case reports of rising thyroid-stimulating hormone (TSH) in people on levothyroxine who took caraway. FDgard’s label asks anyone taking medicines to consult a provider first.

Indigestion is usually harmless, but some symptoms need medical care instead of a remedy. The NHS advises seeing a doctor for indigestion that keeps coming back or causes severe pain, or that comes with unintended weight loss, difficulty swallowing, repeated vomiting, iron-deficiency anemia, a feeling of a lump in the stomach, or blood in vomit or stool, because these can be signs of something more serious. The Austrian leaflet adds that unexplained abdominal pain lasting more than two weeks or getting worse, or pain with fever, yellowing of the skin or eyes (jaundice), vomiting, or blood in the stool, needs a doctor straight away. The German label recommends medical advice for complaints lasting more than a week or returning periodically. Functional dyspepsia is diagnosed from symptoms, so a capsule that helps does not rule out another cause, and new, changing, or persistent upper-abdominal symptoms deserve a proper assessment before months of self-treatment.

06 Questions

Frequently Asked Questions