Peppermint (Mentha piperita) has long been celebrated for its soothing effects on the digestive system and its ability to support immune health. Used for centuries in traditional medicine, peppermint continues to be a popular choice for alleviating digestive discomfort and boosting immunity. With its rich content of menthol and other bioactive compounds, peppermint offers a natural way to address a wide range of health concerns, making it a staple in herbal remedies and modern healthcare alike.
1. Introduction to Peppermint
Peppermint, or Mentha piperita, is a member of the mint family and one of the oldest and most well-known herbal remedies. It was originally discovered in Mentha, a genus collectively named mints, greatly appreciated in Europe and the Mediterranean region for its fragrance, flavoring, and medicinal properties. Although many mint species contain essential oils beneficial for health, peppermint is famous because its oil is high in menthol and menthone prevalent mostly in the United States and the Western world [1]. This aromatic herb has a rich history of being used for both food and healing. Peppermint continues to be cultivated across the globe, notably in Europe and the US, where it is mostly grown instead of spearmint due to its comparatively higher income potential.
From traditional folk medicine to modern scientific research, peppermint has been shown to significantly benefit different physiological systems, especially the digestive and immune systems. In vitro and in vivo studies indicate its various bioactive compounds beneficially affect digestion, appetite, motility, gut microflora, inflammatory response, and mucus production, thereby greatly supporting digestive health. Moreover, it effectively alleviates pain in different gastrointestinal disorders, including spasticity, colic, nausea, and ulcer, thus improving overall digestive health. Its significant anti-inflammatory property driven by menthol actively modulates the immune response, effectively supporting the immune system. Additionally, the various bioactive compounds found in peppermint also demonstrate antioxidant, anti-cancer, anti-diabetic, anti-bacterial, anti-fungal, and anti-viral properties, promoting general health and well-being [2].
1.1. Historical and Cultural Significance
Peppermint has a rich history that dates back over 2000 years, with references found in ancient Egyptian writings, Greek texts, and Roman memoirs. The Egyptians used peppermint in the embalming process, while the Greeks and Romans valued it for culinary and medical purposes [3]. In ancient Rome, it was commonplace among the wealthy, and Roman soldiers used it as a mouth freshener. It was also incorporated in rituals and worship. The Plantagenets brought peppermint to England, where it became popular among both noble families and commoners. Initially used in cooking, it later emerged as a base for herbal remedies in the 17th century. Over the centuries, peppermint and spearmint have gained great popularity. Growing conditions, soil, and climate significantly affect the composition of mint oil, determining its price and quality. Furthermore, mint oils produced by steam distillation contain flavored bitter components and exhibit potent antifungal and antimicrobial activities [1].
2. Chemical Composition of Peppermint
Peppermint is a fragrant perennial herb that has been used as a digestive aid, calming remedy, and treatment for colds and headaches throughout history. Its chemical composition is quite complex and variable and changes widely according to variety, geographic location, climate, and time of harvest. The majority of its predominant active ingredients are terpenoids, with menthol and menthone being emphasized, aside from other oxygenated monoterpenes. Roughly 20 different components account for 95% of the essential oil. Peppermint oil is one of the most widely accepted herbal medicines recommended for the treatment of various digestive symptoms [4].
The plant is effective for indigestion, bloating, abdominal discomfort, and pain in people with functional dyspepsia. It is expected to improve some gastrointestinal symptoms by reducing esophageal, gastric, and hepatic visceral hypersensitivity, decreasing gastric acid secretion, and reducing pyrosis, regurgitation, and bloating. Moreover, peppermint essential oils help to lower bacterial overgrowth in adults with functional dyspepsia and to increase the efficiency of proton-pump inhibitors. This would help alleviate some dyspeptic symptoms in patients with functional dyspepsia. peppermint can enhance or have additive effects with medications such as cyclosporine, tacrolimus, warfarin, and statins. In addition, peppermint extract itself has antioxidant properties and systemic administration protects against aluminum-induced oxidative damage.
2.1. Key Compounds and Their Effects
Peppermint is arguably one of the most popular herbs in the world along with its cousin, spearmint. Both are widely used flavoring agents for foods, candies, teas, oils, cosmetics, health, and pharmaceutical products [1]. Apart from mint’s culinary uses, growing evidence suggests that it may play a role in health enhancement. It is proposed that peppermint is able to achieve a therapeutic effect by enhancing digestive health and stimulating immune support. The main focus of peppermint is the digestive system, and it seeks to explain mint’s mechanism of action on digestive heath. A secondary focus is on mint’s ability to stimulate the immune system. Outside the digestive tract, mint has been found to perform several protective and therapeutic activities in the respiratory system and may also stimulate the immune system. However, mint’s respiratory uses and applications are outside the scope of this research.
The main biologically active components produced by peppermint, menthol, and menthone were examined. It is reported that menthol increases gastric acid secretion and has a soothing effect on gastric irritation. Menthol’s soothing effect on gastric irritation was related to the inhibition of mast cell activation. Mast cells are tissue immune cells that play a key role in inflammatory responses in a number of diseases. Menthol is found to inhibit mast cell activation and the subsequent production of histamine, a major pro-inflammatory factor. Histamine induces gastric acid secretion, and an excessive amount results in gastric mucosal injury and aggravation of diseases such as gastric ulcers and gastroesophageal reflux diseases. Adding each active compound was found to significantly increase the barrier function of Caco-2 cell monolayers, thereby suggesting that both menthol and menthone can help improve intestinal function and integrity.
3. Digestive Health Benefits of Peppermint
Peppermint, that delightful herb with its refreshing and captivating aroma, is not just a flavoring agent for candies anymore. It possesses remarkable medicinal properties that have been cherished for centuries, particularly for digestive health benefits. Back in ancient times, the Greeks and Romans knew about peppermint’s soothing properties for the digestive system, and recent research supports those claims. Peppermint oil is now recognized as an effective drug for digestive problems, including indigestion, bloating, and gas.
Indigestion, also known as dyspepsia, is the most common complaint for digestive health and is one of the most frequent reasons for primary care visits. Symptoms of indigestion usually appear after eating or drinking and may include a sense of fullness, gnawing pain, nausea, or bloating. In general, indigestion is divided into functional or organic, with functional indigestion being related to multiple dysmotility and abnormal sensation. Despite recent advancements in understanding the pathophysiology of functional dyspepsia, effective therapeutic options are still lacking. Peppermint, known for its ability to relieve symptoms of gastrointestinal discomfort, has recently gained attention as a potential treatment option for indigestion. The soothing effects of peppermint are due to its antispasmodic action, which relaxes smooth muscles in the gastrointestinal tract, and its local anesthetic action on the gut wall sensory neurons.
Researchers conducted a study involving healthy volunteers, who received peppermint oil capsules or placebo capsules before a meal. Gastroenteric motility was recorded using a wireless motility capsule (WMC). The results showed that peppermint oil inhibited gastric and intestinal contractions without significantly affecting the overall transit time, duration of symptoms, or degree of symptom relief. The researchers concluded that peppermint oil may offer a potential therapeutic option for functional dyspepsia patients with dysmotility-like symptoms. Additionally, peppermint oil was found to be more effective than placebo in alleviating symptoms and reductions in pain and discomfort scores. Overall, peppermint exhibits great promise as a treatment for functional dyspepsia and warrants further clinical studies. It is already used in various forms, including peppermint tea and peppermint oil capsules, making it readily accessible for individuals seeking over-the-counter relief from indigestion and gastrointestinal discomfort.
3.1. Alleviating Indigestion and Gas
If you’ve ever found yourself squirming in discomfort after a big meal, you know the all-too-familiar pangs of indigestion. This condition, oftentimes accompanied by bloating and gas, can take the fun out of dining. But what if there was a more palatable solution than popping over-the-counter pills? Enter peppermint – the sweet herb that’s been championing digestive woes since the days of yore. It’s no wonder that peppermint oil is featured in a slew of digestive aid supplements, from breath mints to tea.
Studies have consistently found that peppermint – especially its fragrant oil – possesses impressive anti-spasmodic properties. Though the oil can directly relieve cramping in an overactive digestive tract, it’s thought to ease digestion in other ways as well. Some research suggests that peppermint may soothe muscles lining the stomach, enhancing gastric emptying and settling stomach acid back into place. However, those nursing gastric ulcers should exercise caution, as peppermint is also known to lower the barrier pressure between the stomach and esophagus – a potential trigger for heartburn.
Peppermint oil has been harnessed to combat post-surgery gas and is often formulated with ginger and fennel for enhanced effect. A sip of peppermint tea after a huge holiday meal is a time-honored remedy around the world. Even less traditional forms like peppermint-flavored gum can relax your stomach and promote a burrito apology. Most of the research on peppermint’s digestive benefits has focused on enteric-coated capsules of the essential oil, but tea should still be beneficial. Recent research has even found that mint-infused mouthwashes can prevent post-meal bloat and burping.
4. Immune Support Properties of Peppermint
Peppermint is a common kitchen herb of the mint family, widely used in the food and herbal industries worldwide. Over recent years, peppermint has been increasingly used in dietary supplements, herbal teas, and cosmetics. The consumption of peppermint and its oil (essential oil) in foods is approved in several countries, including the United States, Saudi Arabia, and Turkey. Modern and traditional medicinal practices also recognize peppermint’s various health benefits and therapeutic activities.
The leaves (dried or fresh) and oil of peppermint are generally recognized as safe and are widely used in food and medicinal products. Peppermint has been used as a flavor, digestive aid, and breath freshener for centuries. Peppermint oil is traditionally recognized for its use in soothing stomach discomforts, e.g., indigestion, gas, and irritable bowel syndrome. Moreover, peppermint oil has been historically treasured for its cooling effect and is a widely used active ingredient in over-the-counter topical analgesics, cosmetics, oral care products, and pharmaceutical preparations.
As an edible plant, peppermint has been consumed in food and beverages. Peppermint herbal tea has long been consumed as a soothing drink. Peppermint chewing gum has also been popularized for many years. Nevertheless, the knowledge of peppermint in the context of immune support is relatively new. In recent years, peppermint has been extensively studied for its immune support properties with promising results.
Herbal products are widely consumed for their purported health benefits. A broad spectrum of food and dietary products, including peppermint, herbal teas, and herbal supplements, is available to the general public. Traditionally, peppermint has been known for its antimicrobial activity against bacteria and fungi. A few studies reported on the antiviral activity of peppermint in recent years. These studies indicated that peppermint possessed anti-influenza and anti-coronavirus activities.
4.1. Antimicrobial and Antiviral Effects
The antimicrobial constituents of peppermint refer to the phytochemicals found in peppermint that work together to fight bacteria, fungi, viruses, and protozoa. Fresh peppermint has been shown to have an inhibitory effect on E. coli in raw beef during refrigerated conditions. Mint has been shown to be effective against non-pathogenic E. coli with inhibition zones ranging from 14 in raw beef to 17 mm in skim milk. One-hundred percent concentration of peppermint essential oil has been shown to have a noticeable inhibitory effect on the growth of non-pathogenic E. coli strain H1711 [3]. Several phytochemicals are of interest, including menthol, isomenthone, carvone, carvacrol, and methyl acetate, which affect growth by blocking the synthesis of the cellular wall. Peppermint is a source of the active antidiarrheal phytochemical menthol that inhibits the growth of pathogenic E. coli strains EDL933 and HC8. Non-pathogenic and pathogenic E. coli strains that exo-produce shiga toxin 1 and shiga toxin 2 are inhibited at a concentration of 2.5 mg/mL.
The antiviral constituents of peppermint refer to its inhibitory effects on the development and reproduction of viruses where infection or transformation of cells is prevented. In vitro studies have confirmed antiviral activity against Herpes Simplex keratitis from peppermint extract (M. piperita) or its active antiviral metabolite, menthol. Inhibition of viral replication by peppermint has also been demonstrated against the Cowpea Mosaic Virus (CPMV), an economically significant pathogen in beans and other legumes. Peppermint extract has been shown to delay the development of viral infections in sap-inoculated plants, while green mint extract has been shown to have a greater protective effect than dried peppermint extract [4]. Virus replication in host plants is inhibited by peppermint extract. The antiviral activity is attributed to extract components and possibly inhibits virus attachment or absorption (or both) to the free outer surface of the membrane.
5. Methods of Using Peppermint for Health Benefits
Peppermint can be used in various forms, including tea infusions, essential oils, and topical applications, each delivering unique benefits for digestive health and immune support. A peppermint tea infusion, made by steeping fresh or dried leaves in boiling water, is a popular and effective method for soothing digestive discomfort. It can be consumed post-meal to help reduce bloating and gas. Similarly, peppermint essential oils can be applied topically or inhaled to relieve stress and digestive issues, or ingested in capsule form for more targeted benefits.
Tea Infusion
The most widely accepted method of using peppermint for digestive health is through a simple tea infusion. This can be done as follows. Gather a handful of fresh peppermint leaves or a heaping tablespoon of dried mint leaves. Place the leaves in a bowl and pour boiling water over them. Allow the leaves to steep for 10 minutes, then strain out the leaves. If desired, drink unsweetened or with a little honey, sugar, or some milk.
This peppermint tea should be drunk about twenty minutes after meals when overeating has occurred, and possibly also when the initial gas, bloating, and cramps begin. This infusion has been used with great success, although some people find that it requires three to four cups before the digestive crisis is over. For this reason, it is suggested that it be drunk frequently by people who are prone to digestive “attacks”. Several cups throughout the day can be consumed, with the final earthenware cup drunk shortly before bed. In such cases, peppermint tea is drunk daily to prevent digestive pain [4].
The pregnant lady could rely on peppermint infusion as a remedy for her nausea and vomiting, so long as it was made fresh every time! Peppermint tea is very effective for nausea due to other causes, also, although ginger may be needed in addition. If digestive upset is occasioned by stress, anxiety, or feelings of anger, a combination of peppermint, chamomile, and motherwort tea infusions can be drunk until the upset eases.
If peppermint oil is to be used for digestive health, people should avoid its use for heartburn or esophageal reflux. Children under six years of age should never be given peppermint oil, as they are at risk for laryngeal spasms when this oil is used. Peppermint oil should also not be used by anyone who suffers from chronic liver disease. When it is used in excessive amounts, peppermint oil can irritate the skin and mucous membranes. Burns and skin necrosis have been reported.
Water infusion is the preferred extraction because of its greater mildness and traditional use. The water extracts of peppermint do not produce nervous stimulation. In large doses, peppermint water infusion, unlike alcoholic extracts, causes no incapacitating and poisonous effects. A glass of peppermint lemonade is refreshing and healthful. A dash of peppermint in tea is an excellent beverage.
The essential oils Mentha piperita (peppermint) and M. spicata (spearmint) are among the most popular botanical medicines worldwide. Both have long histories in herbal folk medicine [1]. The benefits of peppermint and spearmint in common food saveur-products such as chewing gum, mints, candies, mouthwash, and toothpaste have been shown and successfully marketed. Profiling the chemical composition of these products reveals the diversity of their individual compositions; detection differences among products provide a tool for forensic purposes.
Peppermint essential oil has also been shown to have an inhibitory effect on granulocyte oxidative burst, which has previously only been shown with commercial products (e.g., 5-HT4 receptor agonists) in the peppermint essential oil. Another interesting ancillary finding was that oil-rich peppermint preparations with >90% oil content showed effects even at 37°C. This aligns with the perception of mint oil products often being hot/cooling, which may also link to some digestive effects such as gastric motility (m-3 muscarinic antagonistic) or level of satiety (CCK33 mediated).
5.1. Tea Infusions and Essential Oils
Tea Infusions Tea infusions of peppermint are likely one of the most accepted methods of getting the health benefits of peppermint. Infusions of peppermint tea have even been used to exemplify forgiveness in the New Testament, as it was harvested in gardens with rue; it also purified. In modern times, it’s commonly associated with Greek immigrants who brought koúmina or “Greek mint tea” which can be found at plenty of restaurants [5].
To make the tea infusion of peppermint leaves, add at least a tablespoon of the dried crushed leaves for every cup (10 ounces or more) of water, and steep for 5-10 minutes. The longer the steep, the more intense the flavor. Honey can be added for those with a sweet tooth. If the peppermint flavor is too strong, it can also be blended with other herbs such as chamomile (which mellows the infusion) or lemon balm (which nicely compliments the flavor).
Essential Oils These days, essential oils are the rage in natural health circles, with peppermint oil being the most popular. Peppermint essential oil is especially well known as an effective carminative. In topical applications, often only a couple of drops diluted in unscented carrier oil are needed as peppermint oil possesses a very strong scent and flavor and also can be irritating. Various aromatherapy practices have profited from its invigorating and clarifying scent.
To take peppermint essential oils internally, it should be pharmaceutical-grade and labeled as oils for internal consumption. Peppermint oil is commonly consumed in food and beverages, taking about 1-2 drops for special formulas more effective than herbal or tea preparations. Peppermint oil capsules may be used to mitigate the indirect effects, providing slow time-released benefits without digestive irritation. Always consult an experienced practitioner before using this oil internally or for children.
6. Potential Risks and Side Effects of Peppermint Use
While peppermint is generally regarded as safe for most individuals when used in moderation, several factors should be taken into account before taking peppermint as a supplement or using peppermint essential oil. First, peppermint may interact with medications. Although evidence from human studies is lacking, peppermint may decrease the therapeutic effects of certain medications, particularly cytochrome P450 substrates, by increasing the rate of drug metabolism in the liver. In addition, peppermint may increase the side effects of certain medications [4]. Given the widespread use of peppermint supplements, it is essential for healthcare providers and patients to discuss this issue to ensure their safe and effective use.
There are also concerns about the safety of peppermint due to possible side effects and allergic reactions. Peppermint oil has been associated with heartburn, nausea, and vomiting, and it can cause allergic reactions in sensitive individuals. In general, cosmetic products containing peppermint oil should be patch tested prior to use. Occasional cases of allergic contact dermatitis in some individuals have also been reported after topical application of peppermint oil.
6.1. Interactions with Medications
Mentha piperita (Linn.), which is commonly known as peppermint, is a perennial herbaceous plant from the family Lamiaceae. Menthol is the main ingredient of peppermint oil, with menthyl acetate and menthone as secondary ingredients. It is mostly used in chewing gums, sweet matters, toothpaste, cosmetics, mouthwashes, foods, and pharmaceuticals [4]. Peppermint products have been recommended in folk medicines for alleviating digestive illness, preventing travel sickness, food poisoning, as well as for the treatment of chronic liver diseases.
The typical dosage form is peppermint oil. However, recently peppermint tea has gained popularity as a safe and palatable alternative. Peppermint tea contains lower concentrations of volatile terpenes compared to peppermint oil; therefore, it may not induce any toxic effect. A recent experimental study demonstrated that peppermint tea extract is as effective as peppermint oil in ameliorating multiple gastrointestinal symptoms. There is an increase in interest of peppermint for healthcare since peppermint tea is easier to consume and free of adverse effects, but most of the available literature focuses on the safety of peppermint oil and little is known about the safety of peppermint tea.
Currently, there is no data available regarding potential side effects or drug interactions of peppermint products, including peppermint tea. Therefore, possible side effects and interactions with gastrointestinal motility affecting medications were carefully examined. Peppermint tea induces gastroesophageal reflux without affecting gastric motility in healthy volunteers. Peppermint drugs, commonly used for alleviating digestive problems, may induce serious adverse effects if co-administered with peppermint tea. Peppermint tea should be used with caution in patients using certain medications.
7. Future Research Directions in Peppermint and Health
One emerging area of research focuses on the potential of peppermint and its active component, menthol, in combating COVID-19. Preclinical studies have demonstrated that menthol may inhibit the entry of SARS-CoV-2 and other coronaviruses by interfering with the virus’s ability to bind to the ACE2 receptors on human cells. This binding inhibition is critical because it prevents the virus from entering and infecting the host cells. Additionally, structural analysis suggests that menthol could competitively block the spike receptor-binding domain of the coronavirus, further limiting the virus’s capacity to invade cells. In addition to blocking viral entry, peppermint oil and menthol have shown the potential to reduce coronavirus-induced cytopathic effects, which are the cellular changes caused by viral infection, such as cell damage or death. This finding points to peppermint’s broader antiviral properties, though more research is needed to establish its efficacy as a preventive or therapeutic agent against COVID-19 and similar viral infections.
Beyond its antiviral potential, peppermint has also demonstrated benefits in the treatment of allergic rhinitis, a condition characterized by nasal inflammation due to allergens. Peppermint oil vapor appears to reduce systemic and nasal cavity inflammation by suppressing the production of inflammatory cytokines and chemokines, which are key mediators in allergic responses. This anti-inflammatory action makes peppermint an attractive option for managing the symptoms of allergic rhinitis. A meta-analysis further supported these findings, indicating that peppermint oil could be a useful treatment option for patients suffering from this condition. Peppermint’s dual action on both immune modulation and viral inhibition makes it a promising subject for future research in respiratory and immune health [5].
7.1. Emerging Studies and Areas of Interest
There is a wide range of mint cultivars that are being commercially developed for otherwise rare monoterpenes. For instance, other mints exist that have been bred to be high in carvone. Such cultivars are being investigated in the context of overall health, although it would be worthwhile to look at their health implications in exhaustive detail just like with M. piperita. An extensive review of lesser-known mints could lead to an ever-expanding field of inquiry and subsequent health gains from a wider range of herbaceous plants. Given the increasing interest in mixing plant-based beverages with fermented alcohols, the health implications of these combinations with menthol-rich drinks should also be studied. Further compounding this idea, the rise in popularity of cannabis smoking and consumption is of particular interest to M. piperita. Given that menthol is a known controller of smoking behaviors and that M. piperita has overlapping metabolic pathways with cannabis, the need for the plant to be studied in this field is palpable [5] [4].
References:
[1] D. Kennedy, E. Okello, P. Chazot, M. J. Howes et al., “Volatile Terpenes and Brain Function: Investigation of the Cognitive and Mood Effects of Mentha × Piperita L. Essential Oil with In Vitro Properties Relevant to Central Nervous System Function,” 2018. [PDF]
[2] D. Ma, M. Zhang, and J. Feng, “Dietary Peppermint Extract Inhibits Chronic Heat Stress-Induced Activation of Innate Immunity and Inflammatory Response in the Spleen of Broiler Chickens,” 2024. ncbi.nlm.nih.gov
[3] B. Salehi, Z. Stojanović-Radić, J. Matejić, F. Sharopov et al., “Plants of Genus Mentha: From Farm to Food Factory,” 2018. ncbi.nlm.nih.gov
[4] M. Tafrihi, M. Imran, T. Tufail, T. Aslam Gondal et al., “The Wonderful Activities of the Genus Mentha: Not Only Antioxidant Properties,” 2021. ncbi.nlm.nih.gov
[5] D. Kennedy, E. Okello, P. Chazot, M. J. Howes et al., “Volatile Terpenes and Brain Function: Investigation of the Cognitive and Mood Effects of Mentha × Piperita L. Essential Oil with In Vitro Properties Relevant to Central Nervous System Function,” 2018. ncbi.nlm.nih.gov