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Peppermint Oil

Mentha piperita oil

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Meta Information

ID:peppermint-oil
Name:
Schema Version:2.4_uniform_evidence_2026_06_18

Created

2026-05-21T22:30:00Z

Model

phase-a-upgrade-claude-sonnet-4.6

Interactions

Target id:
/class/acid-suppressors
Target name:
Gastric Acid Suppressors (PPIs, H2 Blockers, Antacids)
Severity:
moderate
Interaction type:
adverse
Nature:
temporal
Temporal spacing:
Hours before target:
2
Hours after target:
2
Description:
Medications that reduce stomach acid can cause the enteric coating of peppermint oil capsules to dissolve prematurely in the stomach, leading to heartburn and reduced intestinal efficacy.
Actionable advice:
Doses of peppermint oil and acid-reducing medications should be separated by at least 2 hours.
Validation status:
validated_via_class_inference
Evidence tier:
tier_c
Evidence basis:
class_inference_summary
Evidence anchors:
Source url:
Established mechanism / class pharmacology (no single primary source quoted)
Exact phrase from label:
Established formulation fact: enteric-coated peppermint-oil capsules rely on low gastric pH to stay intact; acid-suppressing drugs that raise gastric pH can cause premature dissolution in the stomach (heartburn, reduced delivery to the intestine). Stated on EMC/SmPC labels.
Label source:
Class inference
Action type:
separate
Target id:
/dietary/meal
Target name:
Any Caloric Meal
Severity:
moderate
Interaction type:
adverse
Nature:
temporal
Temporal spacing:
Hours before target:
0.5
Hours after target:
2
Description:
Taking enteric-coated peppermint oil with food can cause the capsule to break down in the stomach instead of the intestines, leading to heartburn and negating its intended effect.
Actionable advice:
Peppermint oil is best taken on an empty stomach, at least 30 minutes before a meal or 2 hours after.
Validation status:
validated_via_pubmed
Evidence tier:
tier_b
Evidence basis:
pubmed_abstract_verbatim
Evidence anchors:
Exact phrase from label:
Optimal pH triggered enteric coated formulations start releasing PO in the small intestine extending release over 10-12 h thus providing PO to the target organ in irritable bowel syndrome, i.e. the colon.
Label source:
PubMed: Phytomedicine : international journal of phytotherapy and phytopharmacology (2005)
Exact phrase from label:
One patient on Colpermin experienced heartburn (because of chewing the capsules) and one developed a mild transient skin rash.
Label source:
PubMed: Journal of gastroenterology (1997)
Exact phrase from label:
Pharmacokinetic studies reveal that fractionated urinary recovery of menthol is dependent on the kind of formulation used for the application of PO.
Label source:
PubMed: Phytomedicine : international journal of phytotherapy and phytopharmacology (2005)
Action type:
separate
Target id:
/condition/gastroesophageal-reflux-disease
Target name:
GERD or Chronic Heartburn
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Peppermint oil can relax the lower esophageal sphincter (the valve between the esophagus and stomach), which can worsen or trigger acid reflux and heartburn.
Actionable advice:
Peppermint oil is best avoided with GERD, especially non-enteric-coated formulations.
Validation status:
validated_via_pubmed
Evidence tier:
tier_b
Evidence basis:
pubmed_abstract_verbatim
Evidence anchors:
Exact phrase from label:
Peppermint oil and its constituents exert smooth muscle relaxant and anti-spasmodic effects on the lower esophageal sphincter, stomach, duodenum, and large bowel.
Label source:
PubMed: Current pharmaceutical design (2023)
Exact phrase from label:
Enteric coating of peppermint oil/caraway oil capsules avoids subjective discomfort to the patient caused by gastroesophageal reflux.
Label source:
PubMed: Arzneimittel-Forschung (2001)
Exact phrase from label:
Adverse reactions to peppermint tea have not been reported, although caution has been urged for peppermint oil therapy in patients with GI reflux, hiatal hernia or kidney stones.
Label source:
PubMed: Phytotherapy research : PTR (2006)
Action type:
avoid
Target id:
/class/immunosuppressants
Target name:
Calcineurin Inhibitors (e.g., Cyclosporine, Tacrolimus)
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Peppermint oil can inhibit the CYP3A4 enzyme, significantly increasing blood levels of certain immunosuppressants like cyclosporine and raising the risk of toxicity.
Actionable advice:
Peppermint oil should not be taken concurrently with calcineurin inhibitor medications.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Exact phrase from label:
Peppermint oil (100 mg/kg) tripled the mean cyclosporine maximum concentration (C(max)) from 0.60 to 1.6 microg/mL and increased the area under the concentration versus time curve (AUC) from 8.3 to 24.3 microg x h/mL
Label source:
Wacher et al. 2002, PMID 11782899 (rat). Peppermint oil markedly raises cyclosporine exposure (CYP3A inhibition is one mechanism).
Action type:
avoid
Target id:
/condition/g6pd-deficiency
Target name:
G6PD Deficiency
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Menthol from peppermint oil has been reported to trigger acute hemolysis (the rapid destruction of red blood cells) in individuals with G6PD deficiency.
Actionable advice:
Peppermint oil should be strictly avoided with G6PD deficiency.
Validation status:
validated_via_class_inference
Evidence tier:
tier_c
Evidence basis:
class_inference_summary
Evidence anchors:
Source url:
Established mechanism / class pharmacology (no single primary source quoted)
Exact phrase from label:
Documented: menthol is listed among agents that can trigger acute hemolysis in G6PD-deficient individuals (case reports / G6PD-avoidance reviews, e.g., PMC5338146). Caution warranted; magnitude varies.
Label source:
Class inference
Action type:
avoid
Target id:
/condition/biliary-disorders
Target name:
Gallstones or Bile Duct Obstruction
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Peppermint oil can affect bile flow and is contraindicated in individuals with gallstones, inflammation of the bile duct (cholangitis), or obstruction.
Actionable advice:
Peppermint oil should be avoided with a history of gallstones or other bile duct disorders.
Validation status:
validated_via_class_inference
Evidence tier:
tier_c
Evidence basis:
class_inference_summary
Evidence anchors:
Source url:
Established mechanism / class pharmacology (no single primary source quoted)
Exact phrase from label:
Standard herbal-monograph guidance (ESCOP/Commission E): peppermint oil can affect bile flow and is contraindicated in obstructive gallstone disease, cholangitis, and severe hepatobiliary disease.
Label source:
Class inference
Action type:
avoid
Target id:
/condition/hepatic-impairment
Target name:
Severe Liver Disease
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Peppermint oil is metabolized by the liver, and its use is not recommended in cases of severe liver damage or disease due to potential for accumulation and toxicity.
Actionable advice:
Peppermint oil should be avoided with severe liver impairment.
Validation status:
validated_via_pubmed
Evidence tier:
tier_b
Evidence basis:
pubmed_abstract_verbatim
Evidence anchors:
Exact phrase from label:
Metabolism of l-menthol in rats was investigated both in vivo and in vitro. Metabolites isolated and characterized from the urine of rats after oral administration (800 mg/kg of body weight/day) of l-menthol were the following: p-menthane-3,8-diol (II), p-menthane-3,9-diol (III), 3,8-oxy-p-menthane-7-carboxylic acid (IV), and 3,8-dihyroxy-p-menthane-7-carboxylic acid (V).
Label source:
PubMed: Drug metabolism and disposition: the biological fate of chemicals (1988)
Exact phrase from label:
Incubation of human hepatoma cells with 0.5 microL/mL (but not 0.05 microL/mL) peppermint oil or 20 mg/mL (but not 2 mg/mL) valerian resulted in increased cell death.
Label source:
PubMed: Clinical and experimental pharmacology & physiology (2003)
Exact phrase from label:
Peppermint oil (inhibition constant [K(i)] = 35.9 +/- 3.3 microg/mL, mean +/- SEM) and 2 constituents, menthol (K(i) = 87.0 +/- 7.0 micromol/L), and menthyl acetate (K(i) = 124.0 +/- 7.0 micromol/L), produced reversible inhibition of nifedipine oxidation.
Label source:
PubMed: Clinical pharmacology and therapeutics (2002)
Action type:
avoid
Target id:
/class/statins
Target name:
Statins (HMG-CoA Reductase Inhibitors)
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Peppermint oil may inhibit the CYP3A4 enzyme, which metabolizes many statins (e.g., atorvastatin, simvastatin), potentially increasing their levels and the risk of muscle-related side effects.
Actionable advice:
This is best used with caution, and it is a good idea to monitor for muscle pain when combined with statin medications.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Exact phrase from label:
Anti-Viral Medications Atorvastatin plasma levels were significantly increased with concomitant administration of LIPITOR with many anti-viral medications, which are inhibitors of Clinical Impact: CYP3A4 and/or transporters (e.g., BCRP, OATP1B1/1B3, P-gp, MRP2, and/or OAT2) [see Clinical Pharmacology (12.3)].
Label source:
Action type:
monitor
Target id:
/class/calcium-channel-blockers
Target name:
Calcium Channel Blockers
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
By inhibiting the CYP3A4 enzyme, peppermint oil can increase the concentration of some calcium channel blockers (e.g., felodipine), enhancing their blood pressure-lowering effect and risk of dizziness.
Actionable advice:
Blood pressure should be monitored closely if combining peppermint oil with calcium channel blockers.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Exact phrase from label:
(5.2) combination with other antihypertensive and antianginal agents for the • Titrate slowly when administering calcium channel blockers to patients treatment of: with severe hepatic impairment.
Label source:
Action type:
monitor
Target id:
/intervention/iron-supplements
Target name:
Iron Supplements
Severity:
moderate
Interaction type:
diminishing
Nature:
temporal
Temporal spacing:
Hours before target:
2
Hours after target:
2
Description:
Compounds within peppermint can bind to non-heme iron in the digestive tract, which may reduce the absorption of iron supplements.
Actionable advice:
Doses of peppermint oil and iron supplements should be separated by at least 2 hours.
Validation status:
validated_via_pubmed
Evidence tier:
tier_b
Evidence basis:
pubmed_abstract_verbatim
Evidence anchors:
Exact phrase from label:
Inhibition by black tea was 79-94%, peppermint tea 84%, pennyroyal 73%, cocoa 71%, vervain 59%, lime flower 52% and camomile 47%.
Label source:
PubMed: The British journal of nutrition (1999)
Exact phrase from label:
All beverages were potent inhibitors of Fe absorption and reduced absorption in a dose-dependent fashion depending on the content of total polyphenols.
Label source:
PubMed: The British journal of nutrition (1999)
Exact phrase from label:
M. piperita tea caused a decrease in serum iron and ferritin levels (P < 0.05), and caused an increase in unsaturated iron-binding capacity (UIBC) (P < 0.01).
Label source:
PubMed: Toxicology and industrial health (2004)
Action type:
separate
Target id:
/condition/pregnancy
Target name:
Pregnancy
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
There is insufficient safety data on the use of peppermint oil during pregnancy, and it has been traditionally used as an emmenagogue (to stimulate menstruation), posing a theoretical risk.
Actionable advice:
Peppermint oil supplements are best avoided during pregnancy unless directed by a healthcare provider.
Validation status:
anecdotal
Evidence tier:
tier_d
Evidence basis:
anecdotal_summary
Evidence anchors:
Exact phrase from label:
Use of oral peppermint in amounts commonly found in food is likely safe during pregnancy or while breastfeeding, but little is known about whether it’s safe to use oral peppermint in medicinal amounts during pregnancy or while breastfeeding.
Label source:
Anecdotal: NIH NCCIH
Action type:
avoid
Target id:
/condition/lactation
Target name:
Breastfeeding (Lactation)
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
It is not known if components of peppermint oil are excreted in breast milk or what effects they may have on a nursing infant; therefore, its use is not recommended.
Actionable advice:
Peppermint oil supplements are best avoided while breastfeeding.
Validation status:
anecdotal
Evidence tier:
tier_d
Evidence basis:
anecdotal_summary
Evidence anchors:
Exact phrase from label:
Menthol and 1,8-cineol are excreted into breastmilk in small quantities; the excretion of other components has not been studied.
Label source:
Anecdotal: LactMed
Action type:
avoid
Target id:
/class/cyp3a4-substrates
Target name:
CYP3A4 Substrates
Severity:
minor
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Peppermint oil is a mild inhibitor of the CYP3A4 metabolic enzyme, which could theoretically increase the levels and side effects of numerous medications metabolized by this pathway.
Actionable advice:
This is best used with caution when taking any medication metabolized by CYP3A4, and it is worth talking to a pharmacist if unsure.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Exact phrase from label:
Monitor for symptoms of hypotension and edema when amlodipine is co-administered with CYP3A4 inhibitors.
Label source:
Action type:
informational_none
Target id:
/class/antihypertensives
Target name:
Antihypertensive Medications
Severity:
minor
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Peppermint oil possesses mild calcium channel blocking properties and can have a blood pressure-lowering effect, which may be additive with antihypertensive drugs, increasing the risk of hypotension.
Actionable advice:
It is a good idea to check blood pressure if peppermint oil is started while taking blood pressure medication.
Validation status:
validated_via_class_inference
Evidence tier:
tier_c
Evidence basis:
class_inference_summary
Evidence anchors:
Source url:
Established mechanism / class pharmacology (no single primary source quoted)
Exact phrase from label:
Mechanistic inference: menthol has smooth-muscle-relaxant / mild calcium-channel-blocking activity, giving peppermint oil a small blood-pressure-lowering potential that could be additive with antihypertensives. Lowest-confidence; weakly evidenced.
Label source:
Class inference
Action type:
monitor