Western herbalism

SpearmintMentha spicata

A milder mint with a long folk record for digestion and almost no gut trials; the one controlled study found no effect on reflux or sphincter pressure.

Botanical name

Mentha spicata

Part used

leaf

Also called

Garden mint, Common mint, Mentha viridis

Used in

Western herbalism

Taken for

Gas, Indigestion, Cramping and pain, Nausea

Sold as

tea, capsules, extract, fresh

What is meant by spearmint

Spearmint (Mentha spicata) is the mint most often used in cooking and tea around the Mediterranean and Middle East. Like peppermint it belongs to the Lamiaceae (mint) family, but its oil is dominated by carvone, a caraway-scented compound, where peppermint oil is dominated by menthol.

The leaf is used fresh, dried as a tea, or extracted. Supplement makers also sell a dried water extract standardized to rosmarinic acid, a polyphenol, and an essential oil. Gut products are usually the dried leaf or tea, alone or in a blend.

This entry is short on human data by necessity. Most published trials of spearmint are about hormones or memory, not digestion, and we have listed the few that touch the gut or establish a safety record.

In the traditions

Western herbalism

Ethnobotanical surveys describe spearmint as an everyday digestive herb in Mediterranean and Middle Eastern folk medicine. A survey of Lamiaceae species in Lebanon, which included a spearmint subspecies, found that the family was used mainly against gastrointestinal disorders and infections. A survey of the folk medicine of Lorestan Province in Iran ranked spearmint among the plants cited most often, in a region where most of the recorded plants were used for gastrointestinal, respiratory and skin problems. These are records of what communities report using, not of what trials have shown.

What the plant contains

The oil of spearmint is carvone-rich, with carveol, dihydrocarvone, dihydrocarveol and dihydrocarvyl acetate also present, according to a review of the oil. That review lists antimicrobial, antioxidant and anti-inflammatory activities for these compounds in laboratory work. One laboratory study tested mint oils against Helicobacter pylori bacteria in a dish: a carvone-type spearmint oil inhibited the reference strain at 15.6 to 31.3 mg/L, and carvone alone was among the more active single compounds (50% of clinical strains inhibited at 31.3 mg/L). Those are test-tube concentrations, and no trial has tested spearmint against H. pylori in people. The dried water extract sold as a supplement is standardized to rosmarinic acid instead.

What has been tested in people

We could not find a randomized trial of spearmint tea or leaf for any gut condition. The human data that touch the gut are indirect.

The most relevant study asked a narrow question. In a randomized, double-blind crossover study of healthy volunteers, a 500 mg dose of spearmint, a 0.5 mg flavoring dose and placebo were given with a pressure catheter in the esophagus. Spearmint did not change lower esophageal sphincter pressure (19.6 against 16.0 mmHg at the high dose, not significant) and did not change the number of reflux episodes. The high dose did raise symptom scores (0.35 against 0 at baseline, P = 0.03), which the authors attributed to direct irritation of the lining, not reflux. The study had no peppermint arm, so it does not compare the two mints.

In a randomized trial of 301 patients with nausea after surgery, inhaling a blend of ginger, spearmint, peppermint and cardamom oils lowered nausea scores against saline (P < 0.001), as did ginger oil alone, and fewer antiemetic drugs were requested. Because spearmint was one of four oils, the trial does not show what spearmint contributes.

Outside the gut, spearmint tea twice a day for 30 days lowered free and total testosterone in 42 women with polycystic ovary syndrome (P < 0.05), and an extract at 600 and 900 mg a day for 90 days produced no adverse hormone or lab changes in adults with memory complaints. Both are safety context, not gut results.

Doses used in trials and traditional preparations

No dose has been tested for digestive complaints. The esophageal study gave single doses of 500 mg (high) and 0.5 mg (flavoring). A dried aqueous extract standardized to rosmarinic acid was given at 600 and 900 mg a day for 90 days in the safety trial, and the hormone trial used spearmint tea twice a day for 30 days. The tea (leaf steeped in hot water) is the form the trials and surveys describe. We could not find a European monograph or pharmacopoeial posology for spearmint leaf.

Safety

Spearmint and its extracts are classed as Generally Recognized as Safe in the United States for use as a flavoring, and the safety trial of a dried aqueous extract (600 and 900 mg a day for 90 days in healthy adults) found no severe adverse events and no difference in reported events from placebo. In the esophageal study, six volunteers on the 500 mg dose reported symptoms, against one on placebo, without more reflux, and the authors attributed this to mucosal irritation. The hormone trial found lower testosterone with tea, while the extract trial found no change in FSH, LH or TSH, so the hormone question is not settled. We could not find a safety assessment of spearmint in pregnancy or breastfeeding, and no study in children. Food amounts are not the same as concentrated oil, which was not tested.

Drug interactions

We could not find a published interaction study of spearmint with any medicine, and the European herbal committee has not issued a monograph for it. Two data points are relevant: the extract trial found no change in thyroid-stimulating hormone or the pituitary hormones FSH and LH over 90 days, while the tea trial in women with polycystic ovary syndrome found lower testosterone and higher LH and FSH over 30 days. Anyone taking hormone-related medicines may see the second finding as relevant, and the evidence does not settle it. The catalog’s own drug rules are listed automatically on this page.

Products in the catalog with spearmint

These catalog entries list spearmint or one of its preparations among their active ingredients. Each page shows the amount on the label, the trials behind it and what buyers report.

Related herbs

Questions people ask

Sources

• Bulat R et al., "Lack of effect of spearmint on lower oesophageal sphincter function and acid reflux in healthy volunteers", Aliment Pharmacol Ther 1999;13(6) pubmed.ncbi.nlm.nih.gov/10383511
• Hunt R et al., "Aromatherapy as treatment for postoperative nausea: a randomized trial", Anesth Analg 2013;117(3):597-604 pubmed.ncbi.nlm.nih.gov/22392970
• Lasrado JA et al., "Safety and tolerability of a dried aqueous spearmint extract", Regul Toxicol Pharmacol 2017;86:167-176 pubmed.ncbi.nlm.nih.gov/28286189
• Grant P, "Spearmint herbal tea has significant anti-androgen effects in polycystic ovarian syndrome. A randomized controlled trial", Phytother Res 2010;24(2):186-188 pubmed.ncbi.nlm.nih.gov/19585478
• Zhang LL et al., "Bioactive properties of the aromatic molecules of spearmint (Mentha spicata L.) essential oil: a review", Food Funct 2022;13(6):3110-3132 pubmed.ncbi.nlm.nih.gov/35212344
• Piasecki B et al., "Composition and Anti-Helicobacter pylori Properties of Essential Oils Obtained from Selected Mentha Cultivars", Molecules 2023;28(15):5690 pubmed.ncbi.nlm.nih.gov/37570659
• Khoury M et al., "Report on the Medicinal Use of Eleven Lamiaceae Species in Lebanon and Rationalization of Their Antimicrobial Potential by Examination of the Chemical Composition and Antimicrobial Activity of Their Essential Oils", Evid Based Complement Alternat Med 2016 pubmed.ncbi.nlm.nih.gov/28053641
• Mehrnia M et al., "Ethnopharmacological studies of medicinal plants in central Zagros, Lorestan Province, Iran", J Ethnopharmacol 2021;280:114080 pubmed.ncbi.nlm.nih.gov/33798662