At a glance
Common names: Mānuka, kahikātoa, New Zealand tea tree
Botanical name: Leptospermum scoparium
Plant family: Myrtaceae
Native status: Indigenous to New Zealand and also native to parts of Australia
Natural habitat: Coastal areas, wetlands, river gravels, scrub and dry hillsides
Parts discussed in traditional use: Leaves, bark, sap, gum, young shoots and seed capsules
Important constituents: Volatile essential-oil compounds, including β-triketones and sesquiterpenes; the composition varies between plants and regions
Associated products: Mānuka honey, mānuka essential oil, leaf extracts and traditional water-based preparations
Traditional context: Rongoā Māori, practical technologies and early New Zealand herbal practice
Modern research: Antimicrobial activity in laboratory studies, chemical investigations and research into the potential applications of mānuka honey and essential oil
Important distinction: The tree, its essential oil and mānuka honey are different materials. Evidence relating to one should not automatically be applied to the others.
Getting to know mānuka
Mānuka is one of Aotearoa New Zealand's most recognisable native shrubs. Depending on its growing conditions and form, it can remain a low, spreading plant or develop into a substantial shrub or small tree reaching several metres in height.
Its narrow, pointed leaves are generally small and firm, while its flowers are usually white, sometimes flushed with pink. Each flower has five petals and a distinctive centre of stamens, often dark red in appearance. Woody seed capsules can remain on the plant for extended periods, providing another useful identification feature.
Mānuka belongs to the Myrtaceae family, which also includes pōhutukawa, rātā, eucalyptus and guava. Many members of this family contain aromatic compounds, and several have attracted interest in traditional plant use and modern natural-products research.
The species grows in diverse environments, from coastal margins and river gravels to wetlands and dry hillsides. It tolerates a broad range of conditions and can establish rapidly in open ground following disturbance. This makes it important in ecological succession and restoration planting, where it may provide shelter for slower-growing native species.
Although mānuka is widely associated with New Zealand, it is not strictly endemic to the country. It also occurs naturally in parts of Australia, including Tasmania.
Mānuka or kānuka?
Mānuka is often confused with kānuka (Kunzea ericoides and related taxa). The plants look similar when viewed from a distance, but they belong to different genera.
Some useful identification differences are:
- Leaves: Mānuka generally has small, firm leaves with sharp tips. Kānuka leaves usually lack the same sharply pointed tip.
- Flowers: Mānuka typically has relatively large flowers occurring singly along the branches. Kānuka commonly has smaller flowers appearing in clusters.
- Bark: Mānuka's bark is generally shorter, papery and flaky, whereas mature kānuka commonly develops longer, leathery strips of bark.
These are useful general features rather than a replacement for botanical identification, as both groups are variable.
This distinction matters when interpreting traditional knowledge and scientific research. Mānuka oil and kānuka oil have different chemical compositions, and studies of one cannot simply be treated as evidence for the other.
The history behind the name tea tree
Early European visitors and settlers in New Zealand used mānuka leaves to prepare a drink resembling tea. The name New Zealand tea tree reflects this history, although mānuka is botanically unrelated to the familiar tea plant, Camellia sinensis.
The leaves provide an aromatic, somewhat resinous scent, which helps explain their appeal in a hot-water infusion.
Mānuka has also been valued for its hard, durable wood. Historical records describe the use of its branches and timber for paddles, digging implements, tools, weapons and other practical objects. Its bark was used in applications including containers and protective roofing layers.
These uses illustrate that mānuka was valued for far more than its possible medicinal properties. It offered materials, aromatic foliage, useful wood and a nectar source for insects.
Its ecological importance continues today. Mānuka flowers provide pollen and nectar for bees and other visiting insects. The species can also help stabilise exposed ground and create conditions that favour the return of more complex native vegetation.
Mānuka in rongoā Māori
Mānuka has an extensive recorded history of traditional medicinal use in Aotearoa New Zealand.
Historical ethnobotanical accounts describe the use of leaves, bark, sap, gum, young shoots and seed capsules. The reported applications include fever, digestive complaints, coughs, colds, skin conditions and musculoskeletal discomfort.
The records were collected at different times by different observers. Some describe Māori knowledge and practice; others reflect the interpretations of early European writers and herbalists. These accounts are valuable, but they do not necessarily represent a single uniform practice shared by every iwi, hapū or whānau.
Rongoā Māori is a living body of knowledge that encompasses relationships with people, whenua and the natural environment, as well as plant remedies and other approaches to healing. Its cultural context is important when interpreting historical descriptions of medicinal plants.
Leaves and traditional infusions
Historical accounts describe mānuka leaves being infused or boiled in water. Some records associate these preparations with fever, urinary complaints, stomach discomfort and other internal symptoms.
Leaves were also used in aromatic preparations and steam-based practices associated with colds and respiratory complaints.
These records show the variety of ways the plant was used historically. They do not establish that every preparation has been clinically demonstrated to treat the conditions mentioned.
Bark and seed capsules
The bark and seed capsules also feature prominently in historical medicinal descriptions.
Some records describe bark decoctions associated with diarrhoea and dysentery, while boiled seed capsules were used in traditional preparations for digestive complaints. Other historical accounts describe topical applications for bruises, inflammation and skin problems.
Such preparations may differ substantially in their chemical composition from leaf infusions or contemporary commercial extracts. It would therefore be inappropriate to regard all mānuka preparations as equivalent.
Mānuka gum
Historical accounts also describe a sweet, gum-like exudate known as pia mānuka. It was recorded as being used externally for burns and scalds and, in some historical accounts, given internally to infants.
These are records of past practice, not recommendations for current use. The composition and safety of such material have not been established sufficiently to justify treating it as a modern wound product or infant remedy.
Preserving traditional knowledge responsibly
Historical descriptions are important because they preserve knowledge that might otherwise be lost. However, they need to be interpreted with an understanding of their origins and limitations.
A recorded use is evidence that a plant was used for a particular purpose. It is not necessarily evidence that the preparation was effective, that the species was always identified correctly, or that the same practice is appropriate today.
Respectful discussion of mānuka recognises its place in rongoā Māori while distinguishing cultural knowledge from contemporary clinical evidence.
What does mānuka contain?
Mānuka contains a complex mixture of naturally occurring chemicals. The profile depends on the plant part, growing location, plant age, season and preparation method.
The chemistry of the foliage is particularly important when discussing mānuka essential oil, while honey produced from the plant's nectar has a different composition.
Volatile essential-oil compounds
Mānuka essential oil is generally produced through steam distillation, commonly using leaves and young stems.
The resulting oil contains a mixture of volatile compounds, including sesquiterpenes and specialised molecules known as β-triketones.
The proportions of these substances can vary considerably. Researchers have documented substantial differences in essential-oil chemistry between plants from different parts of New Zealand.
For example, some oils from the East Cape region are particularly rich in β-triketones, while oils from other regions may have higher proportions of monoterpenes or different sesquiterpenes.
This variation is sometimes described in terms of chemotypes: plants of the same species that produce different characteristic chemical profiles.
It explains why two products sold as mānuka oil may have different aromas and chemical compositions.
Leptospermone and related β-triketones
Leptospermone is one of the best-known compounds associated with mānuka essential oil. Related β-triketones, including grandiflorone and flavesone, have also attracted research interest.
These compounds have demonstrated antimicrobial activity in certain laboratory experiments. They are among the reasons mānuka oil is investigated for possible use in topical products and other applications.
However, laboratory activity does not automatically establish that the whole oil is a safe or effective treatment for an infection. The concentration, formulation, contact time, safety profile and type of microorganism all affect the relevance of an experimental result.
Sesquiterpenes
Sesquiterpenes are a diverse group of volatile plant compounds. Several have been identified as components of mānuka essential oil, including calamenene and cadinene-related compounds.
Their proportions contribute to the oil's distinctive aroma and chemical characteristics.
Mānuka oil is not a single active ingredient. It is a mixture whose constituents may vary between samples, which creates challenges when attempting to standardise a preparation for medicinal use.
Mānuka honey: a different chemistry
Mānuka honey is produced by bees collecting nectar from mānuka flowers. It is not an essential oil or a concentrated leaf extract.
Honey has its own chemical profile, including sugars, organic acids, phenolic compounds and other minor constituents.
One compound that receives considerable attention is methylglyoxal, commonly abbreviated as MGO. In mānuka honey, methylglyoxal develops largely from dihydroxyacetone, or DHA, which is present in mānuka nectar.
MGO contributes to the distinctive non-peroxide antimicrobial activity of mānuka honey.
Other compounds also contribute to honey's properties, and the resulting activity depends on the complete composition of the honey rather than a single measurement alone.
The presence of MGO in mānuka honey should not be used to infer that mānuka essential oil has the same chemical properties. The two products are produced from different plant materials and processes.
Why the form of the product matters
A leaf infusion, essential oil, topical leaf extract and mānuka honey may all originate from the same species, but they are chemically different preparations.
An aqueous infusion extracts compounds that dissolve in water. Steam distillation collects volatile constituents, while bees transform flower nectar into honey through their own biological processes.
These differences affect the composition, concentration, route of use and safety considerations of each product.
What does modern research tell us?
Modern research into mānuka covers several related but distinct areas: the chemistry of the essential oil, antimicrobial experiments, investigations into mānuka honey and the potential uses of mānuka-derived ingredients.
The evidence is strongest for demonstrating that certain preparations possess measurable biological activity in laboratory settings. The evidence is more limited when the question is whether a particular product safely and reliably treats a medical condition in people.
Research into mānuka essential oil
A major review published in 2020 examined research on the antimicrobial, antiparasitic and other biological activities of mānuka essential oil.
The review found substantial laboratory evidence suggesting that the oil and some of its constituents can affect a range of microorganisms. It also discussed variation in oil composition between geographical regions and plant chemotypes.
This is important because the activity of one oil sample cannot necessarily be assumed for every product labelled mānuka oil. Different chemical profiles may result in different levels of activity.
The review concluded that additional clinical research, standardisation and safety assessment were necessary before the oil's therapeutic potential could be established more confidently.
In practical terms, the research provides a scientific reason to investigate mānuka oil further. It does not establish a universally effective concentration, a standard treatment dose or proof that the oil can replace conventional antimicrobial treatments.
Antimicrobial activity in laboratory tests
Some mānuka-oil constituents, especially certain β-triketones, have shown activity against bacteria in controlled experiments.
Research has investigated effects against organisms relevant to food safety, skin infection and antimicrobial resistance, including selected strains of Staphylococcus aureus.
The exact outcome depends on the compound, test method, concentration and microorganism. Activity observed in a laboratory dish cannot be assumed to occur to the same extent on human skin or inside the body.
The oil may also irritate tissues or have other unwanted effects at concentrations required to achieve biological activity.
Consequently, the presence of antimicrobial activity does not mean that mānuka essential oil is an established treatment for an infected wound, acne, fungal infection or systemic illness.
Mānuka honey and wound care
Mānuka honey has a separate research history, including laboratory studies and investigations of its use in wound-care products.
Honey has several properties relevant to wound management. Its high sugar concentration can create an osmotic environment, its natural acidity can influence the wound environment, and mānuka honey contains compounds associated with non-peroxide antimicrobial activity.
Certain purpose-made medical-grade honey products are used in wound care. However, these products are manufactured and quality-controlled for medical use and should not be considered equivalent to ordinary food honey.
The evidence for a specific wound-care product needs to be considered in relation to the wound type, clinical setting and treatment plan.
It would be misleading to conclude that every jar of mānuka honey will heal every wound, prevent infection or outperform other treatments.
Authenticity and honey quality
Mānuka honey's commercial value has made reliable identification particularly important.
New Zealand's Ministry for Primary Industries uses a scientific definition for mānuka honey exported from New Zealand. It involves a combination of four chemical attributes associated with nectar and a DNA marker associated with mānuka pollen. These markers help determine whether honey qualifies as monofloral or multifloral mānuka honey.
This authenticity testing is different from simply measuring MGO.
An MGO figure describes the concentration of that particular compound. It does not, by itself, establish every aspect of authenticity, manufacturing quality, suitability for medical use or likely benefit for an individual.
Consumers should therefore distinguish between claims of botanical identity, chemical strength and clinical performance.
What about traditional respiratory and digestive uses?
Historical records describe mānuka leaf and bark preparations in association with coughs, colds, fever, diarrhoea and dysentery.
The existence of these records is important to mānuka's ethnobotanical history, but modern clinical evidence is insufficient to establish that homemade leaf infusions or bark decoctions safely treat these conditions.
A respiratory infection, severe gastrointestinal illness or persistent fever may require medical evaluation. The use of a traditional botanical preparation should not delay appropriate care.
The overall picture
Mānuka is scientifically interesting because its essential oil and honey contain distinct mixtures of compounds with measurable biological activity.
Research supports further investigation of the essential oil, while selected medical-grade honey products have specific applications in wound care. However, these findings cannot be generalised to every preparation derived from the plant.
The most accurate approach is to discuss each product separately, assess the quality of the evidence for its intended use and avoid broad claims that exceed what has been demonstrated.
Understanding mānuka honey
Mānuka honey deserves its own discussion because it is often confused with mānuka leaf extracts and essential oil.
The honey is produced from flower nectar by bees. Its chemical profile depends on the nectar source, the activity of bees, maturation, storage and processing.
What makes mānuka honey distinctive?
Mānuka honey has a distinctive combination of chemical markers and has been investigated for non-peroxide antimicrobial activity.
MGO is an important constituent associated with this activity. It develops from DHA in mānuka nectar during the formation and maturation of the honey.
However, honey is a complex food rather than a single-compound preparation. Its activity cannot be understood from MGO concentration alone, and the different measures used to classify or grade honey do not all answer the same question.
For consumers, it is useful to distinguish:
- Authenticity: Whether the product meets the relevant definition for genuine New Zealand mānuka honey.
- Chemical measurement: The concentration of a particular constituent, such as MGO.
- Intended use: Whether the product is food, a cosmetic ingredient or a purpose-made medical product.
One of these attributes does not automatically establish the others.
Food honey versus medical-grade honey
Ordinary mānuka honey is a food. Medical-grade honey products are manufactured for medical use and are subject to additional product-quality requirements.
Food-grade honey is not sterile and should not be substituted for a medical wound dressing when proper wound care is required.
If honey-based wound care is being considered, use an appropriate medical-grade product according to its instructions and seek professional guidance when the wound is deep, infected, extensive or slow to heal.
Eating mānuka honey
Mānuka honey can be enjoyed as a food. Its distinctive flavour and chemical composition make it a valued product, but it is still primarily a sugar-rich food.
A higher MGO rating should not be interpreted as proof that eating the honey will prevent infections, improve immunity or treat a medical condition.
Honey must not be given to infants younger than 12 months because of the risk of infant botulism. This restriction applies to mānuka honey as well as other honeys.
People with diabetes should also consider honey's carbohydrate and sugar content within their individual dietary and treatment plan.
Mānuka essential oil and topical products
Mānuka essential oil is produced by distilling volatile compounds from the plant's foliage, stems or other suitable material.
The oil is often used as an ingredient in cosmetic and personal-care products. Its aromatic qualities and laboratory antimicrobial activity have led to interest in products designed for skin cleansing and related uses.
However, the fact that an ingredient has antimicrobial activity does not automatically mean it is appropriate for direct application to skin, nor does it establish that a particular cosmetic will treat a skin condition.
Essential oil versus infused oil
An essential oil is a concentrated volatile extract obtained through distillation or another extraction method designed to collect volatile constituents.
An infused oil is made by soaking plant material in a carrier oil. It may extract some oil-soluble compounds, but its composition is generally different from that of a distilled essential oil.
These preparations should not be assumed to have the same strength or safety profile.
Formulation and dilution
Essential oils are concentrated and may cause skin irritation or allergic reactions. Suitability depends on the product's composition, concentration, intended use and individual sensitivity.
Do not ingest mānuka essential oil or apply it undiluted to the skin unless a product specifically formulated and labelled for that use provides appropriate instructions. Avoid contact with the eyes and other sensitive tissues.
A product's aroma or natural origin does not guarantee safety. Proper formulation, quality control and usage instructions remain important.
Choosing a product thoughtfully
For commercial mānuka products, check the ingredient list, botanical identity, intended use and relevant quality information.
A cosmetic product should be assessed according to its formulation and cosmetic purpose. A medical product requires evidence and quality controls appropriate to its clinical use.
Be cautious of claims that one preparation can simultaneously treat infections, regulate hormones, boost immunity, heal every wound and cure skin disease. Such broad claims require strong evidence for each individual outcome.
Growing mānuka at home
Mānuka is a versatile native shrub that can suit a range of gardens and restoration projects.
It naturally grows in environments ranging from wet ground to exposed hillsides and relatively dry sites. Mature plants can tolerate drought, wind, frost and some waterlogged conditions, although establishment requirements and the performance of individual forms can vary.
Light and soil
Mānuka generally grows well in an open position with good light. It can establish in comparatively poor or acidic soils and often grows rapidly where vegetation has been disturbed.
Because the species is variable, choose a plant suitable for the local climate, soil and garden conditions rather than assuming that every nursery cultivar performs identically.
Propagation
Mānuka can be propagated from seed and, depending on the plant and method, from cuttings.
Fresh seed is a practical option for growing native plants, while selected cultivars may be propagated vegetatively to maintain particular characteristics.
For home gardens, a reputable native-plant nursery can help select a suitable plant and explain its expected mature size and growing requirements.
Flowers and wildlife
The white or pink flowers provide nectar and pollen for visiting insects, making mānuka useful in wildlife-friendly plantings.
Mānuka can also function as a nurse crop in restoration areas. It establishes quickly in open ground, providing shelter and helping create conditions for slower-growing native species to become established.
Planting responsibly
Mānuka varies across its natural range. For restoration planting close to indigenous vegetation, locally sourced plant material is generally preferable so that the planting better reflects local populations and ecological conditions.
Growing mānuka for garden and restoration purposes is distinct from harvesting it for medicinal preparations. Plants exposed to sprays or contaminants should not automatically be treated as suitable sources of herbal material.
Harvesting, sourcing and sustainability
Mānuka remains widespread in New Zealand, but responsible harvesting still matters.
Before collecting plant material, establish who owns the land, whether permission is required and whether local restrictions apply. Avoid damaging trees or removing excessive foliage, bark or other material.
Historical records describe the use of multiple plant parts, but they do not provide a single modern harvesting protocol suitable for every purpose.
For scientific research or product development, it is important to record the botanical identity, plant part, location, season and preparation method. These details help explain differences in chemical composition between samples.
Commercial sourcing requires additional attention to quality control. Suppliers should identify the plant accurately and provide suitable information about the extraction method, intended use and product composition.
For mānuka honey, authenticity testing and reliable labelling help distinguish genuine product from honey derived from other floral sources or products that may not meet the relevant standard.
Safety considerations
Mānuka's traditional history and modern research interest do not establish that all mānuka preparations are safe for every person.
The plant, essential oil and honey require different safety considerations.
Pregnancy and breastfeeding: Reliable safety information for medicinal mānuka leaf and bark preparations is limited. Avoid medicinal use of homemade preparations during pregnancy or breastfeeding without advice from an appropriate health professional.
Children and infants: Do not give homemade medicinal preparations to children based on historical recipes. Honey, including mānuka honey, must never be given to infants under 12 months because of the risk of infant botulism.
Essential oil: Do not ingest mānuka essential oil. It is concentrated, may irritate skin and can cause adverse reactions. Follow product-specific instructions, avoid the eyes and other sensitive tissues, and seek professional advice before use on children or people with sensitive skin.
Skin allergies: Natural aromatic ingredients can cause contact irritation or allergy. Stop using a product if a reaction develops. A small-area test may identify some immediate skin reactions, but it cannot guarantee that sensitisation will not occur.
Wounds and burns: Do not use ordinary food honey or homemade plant preparations as substitutes for medical wound-care products. Serious burns, deep wounds, infected injuries and wounds that are not healing require appropriate assessment. Medical-grade honey products should be used according to their instructions and, where necessary, professional advice.
Respiratory and digestive complaints: Historical mānuka preparations are not substitutes for appropriate diagnosis and treatment. Severe breathlessness, persistent fever, blood in the stool, bloody diarrhoea, severe abdominal pain or signs of dehydration warrant prompt medical attention.
Medicines and ongoing health conditions: Clinical interaction data for many homemade mānuka preparations and concentrated essential oils are limited. Discuss a specific product with a qualified health professional or pharmacist if you take regular medicines or have a chronic condition.
Product quality: For essential oils, choose products with clear labelling, suitable quality controls and explicit intended-use directions. For honey, distinguish food products from those manufactured for medical use.
The lack of comprehensive safety data is an important consideration in its own right. It is not evidence that every traditional preparation or commercial product is harmful, but neither does natural origin guarantee safety.
Understanding mānuka's place in modern herbal practice
Mānuka is a good example of how a plant can have several different identities in contemporary herbal discussions.
As a native shrub, it has ecological, cultural and practical significance. Its foliage and bark feature in historical accounts of rongoā Māori. Its essential oil has attracted interest because certain chemical constituents show antimicrobial activity in laboratory research. Its nectar also provides the basis for a distinctive honey that has been investigated for wound-care applications.
These areas are connected through the same plant, but they should not be treated as interchangeable.
The chemistry of mānuka essential oil differs from that of mānuka honey. The evidence supporting a medical-grade honey dressing does not automatically establish a benefit from eating a jar of mānuka honey. Likewise, laboratory findings about essential oil do not establish that it safely treats an infection when applied at home.
An informed herbal approach asks which preparation has been studied, how it was made, what outcome was measured and whether the evidence applies to the person and purpose in question.
This approach respects mānuka's traditional history while allowing modern research to be assessed carefully and realistically.
In summary
Mānuka (Leptospermum scoparium), also known as kahikātoa, is a native New Zealand shrub with an extensive history of practical and traditional medicinal use.
Historical accounts describe the use of its leaves, bark, gum, sap and seed capsules in preparations associated with fever, digestive complaints, respiratory symptoms and skin care. The plant's timber and aromatic leaves also had important practical uses.
Modern research has identified a varied essential-oil chemistry, including β-triketones such as leptospermone. Some of these constituents show antimicrobial activity in laboratory experiments, but further clinical research and standardisation are needed to establish the therapeutic value and safety of mānuka essential oil.
Mānuka honey is a separate product produced from flower nectar. Certain medical-grade honey products are used in wound care, but ordinary food honey is not equivalent to a medical dressing, and eating mānuka honey should not be promoted as a proven treatment for infection.
Mānuka is best understood through its botanical identity, cultural history, ecological value and the evidence relevant to each preparation. Respect for traditional knowledge and careful interpretation of modern research can coexist without overstating what has been demonstrated.
Sources and further reading
1. Department of Conservation Te Papa Atawhai. Mānuka/kahikātoa and kānuka. Botanical identification, habitat, ecology and traditional material uses. https://www.doc.govt.nz/nature/native-plants/manuka-kahikatoa-and-kanuka/ 2. Manaaki Whenua – Landcare Research, Ngā Rauropi Whakaoranga. Leptospermum scoparium. Mānuka. Kahikātoa. Ethnobotanical records of historical Māori uses of mānuka leaves, bark, gum, sap and seed capsules. https://rauropiwhakaoranga.landcareresearch.co.nz/names/34969a5f-698d-437d-8a84-c71dd21351a5 3. Te Ara – The Encyclopedia of New Zealand. Rongoā: medicinal use of plants. Historical context for Māori plant medicine, including recorded uses of mānuka. https://teara.govt.nz/en/rongoa-medicinal-use-of-plants 4. Mathew, C. et al. (2020). “Mānuka Oil—A Review of Antimicrobial and Other Medicinal Properties.” Pharmaceuticals, 13(11), 343. Reviews oil composition, laboratory antimicrobial results and the need for further clinical and safety research. https://doi.org/10.3390/ph13110343 5. Porter, N. G. et al. (2004). “Essential oils from New Zealand mānuka: triketone and other chemotypes of Leptospermum scoparium.” Phytochemistry, 65(9), 1255–1264. Research into regional variation in essential-oil composition. https://pubmed.ncbi.nlm.nih.gov/15184010/ 6. New Zealand Ministry for Primary Industries. Ensuring mānuka honey is authentic. Explains the chemical and DNA markers used to distinguish authentic New Zealand mānuka honey and classify it as monofloral or multifloral. https://www.mpi.govt.nz/food-business/honey-bee-products-processing-requirements/manuka-honey-testing 7. Chemical Elements and the Quality of Mānuka (Leptospermum scoparium) Honey (2021). Research on mānuka honey composition, including methylglyoxal and other markers relevant to its quality and biological activity. https://pmc.ncbi.nlm.nih.gov/articles/PMC8303644/ This guide is educational and is not a substitute for individual medical advice or guidance from a qualified rongoā Māori practitioner.