At a glance
Common names: Horopito, red horopito, mountain horopito, New Zealand pepper tree
Botanical name: Pseudowintera colorata
Plant family: Winteraceae
Native status: Endemic to New Zealand
Natural distribution: North Island, South Island and Stewart Island
Natural habitat: Coastal, lowland and montane forest margins and shrubland
Traditional plant part: Primarily the leaves, with historical accounts also referring to bark and sap
Key compound: Polygodial, a pungent sesquiterpene dialdehyde
Traditional context: Rongoā Māori and historical New Zealand herbal practice
Modern research: Antifungal activity in laboratory studies, chemical investigations and limited clinical research involving a specific horopito-containing product
Important distinction: Evidence that polygodial inhibits fungi in laboratory experiments does not mean every horopito preparation is an effective or safe treatment for a fungal infection.
Getting to know horopito
Horopito is a striking native evergreen shrub best known for its leathery leaves, which can be patterned with red, pink or burgundy markings against a green or yellowish-green background.
The plant can grow to approximately 3.5 metres tall, although its size and shape depend on the environment. It is found across the North, South and Stewart Islands, generally around the edges of coastal, lowland and montane forests and in shrubland.
The leaves are alternate along the branches, relatively small and oval-shaped, with gently wavy margins. Their undersides are often pale, glaucous or whitish, sometimes with a pinkish tinge. When crushed or chewed, the foliage has a pronounced peppery taste that can create a hot, burning sensation in the mouth.
This pungency is not merely a culinary curiosity. It is associated with the plant's natural chemical defence system, including the compound polygodial, which has attracted scientific interest for its antifungal properties.
Horopito belongs to the Winteraceae family, an ancient lineage of flowering plants. Its family relationships make it botanically distinct from familiar culinary peppers such as black pepper (Piper nigrum), chilli peppers (Capsicum species) and horseradish (Armoracia rusticana).
Despite its common name, horopito is not a true pepper. Its distinctive taste arises from a different chemical profile.
Horopito and lowland pepper tree
The name horopito is used for more than one native Pseudowintera species, particularly Pseudowintera colorata and Pseudowintera axillaris.
The species covered in this guide is P. colorata, often called red horopito or mountain horopito. Its red-blotched leaves are a useful identification feature, and its foliage is notably pungent.
Pseudowintera axillaris, commonly known as lowland pepper tree, typically has greener, shinier leaves without the same characteristic white undersides and strong peppery taste.
This distinction is important when interpreting traditional records and scientific research. Historical accounts sometimes use only the common name horopito, making it difficult to establish which species was involved. The two species also have different chemical profiles, and polygodial has been isolated from P. colorata but was not detected in the cited early investigation of P. axillaris.
Accurate identification helps prevent findings about one species from being incorrectly attributed to another.
Horopito in rongoā Māori
Horopito has an established place in historical accounts of rongoā Māori and traditional New Zealand plant medicine.
Ethnobotanical records describe the leaves being used in preparations associated with skin complaints, stomach pain and toothache. Other historical accounts refer to horopito as a pungent or stimulating plant and describe the use of its bark or sap for various complaints.
The traditional record is not entirely straightforward. Some historical writers used the name horopito without identifying the species precisely, while others described plants that can be associated with either P. colorata or P. axillaris.
The available evidence therefore supports a history of traditional use associated with horopito, but not every reported application can be assigned confidently to P. colorata alone.
Leaves and skin complaints
Historical records describe bruised horopito leaves being soaked in water or prepared as a decoction for certain skin complaints. Other accounts describe chewed leaves being applied to wounds.
Some reports associate the plant with paipai, a historical term used for particular skin complaints, including conditions understood at the time to be fungal or infectious.
These accounts are important records of traditional practice. They do not establish that a homemade horopito preparation is a safe or effective treatment for ringworm, infected skin or other modern clinical diagnoses.
The identity of the original plant, the preparation used and the circumstances of treatment may not have been recorded fully.
Stomach discomfort
Historical writers also recorded the use of horopito for stomach pain and digestive complaints. In some accounts, the plant was described as a remedy for diarrhoea.
These records reflect the historical place of horopito in plant medicine, but they do not establish an appropriate modern dose or show that horopito is suitable for every cause of digestive discomfort.
The plant's pungency is also relevant to safety. A substance that produces a strong burning sensation should not be assumed to be soothing to the digestive tract.
Toothache and traditional pain relief
Some historical ethnobotanical accounts describe chewing horopito leaves for toothache, and the plant has sometimes been called the Māori painkiller in contemporary herbal literature.
It is important not to turn that description into an unsupported clinical claim. Historical use for discomfort does not establish that the plant reliably relieves dental pain or treats the underlying cause.
Toothache can result from tooth decay, infection, gum disease or other problems that may require dental treatment. A pungent plant preparation should not be used in place of appropriate assessment.
Respecting cultural context
Rongoā Māori is a living system of healing that includes plant-based preparations, physical therapies, spiritual dimensions and relationships with people and whenua.
Historical written accounts are useful, but they do not capture all the knowledge, tikanga or circumstances associated with traditional practice. Practices can differ among iwi, hapū, whānau and practitioners.
A responsible herbal guide should preserve the historical record while distinguishing it from modern recommendations and recognising the importance of appropriate cultural guidance.
Why does horopito taste so peppery?
Horopito's characteristic pungency is closely associated with polygodial, a naturally occurring compound in its leaves.
Polygodial belongs to a group of chemicals known as sesquiterpene dialdehydes. It has a distinctive structure and has been investigated for its effects on fungi and other biological systems.
Unlike the piperine found in black pepper or the capsaicin found in chilli, polygodial has its own chemical structure and biological properties.
The sensation produced by horopito leaves is therefore not simply the same as eating chilli or black pepper. The intensity can vary with the plant material and its chemical composition.
A defensive role in the plant
Pungent plant compounds often contribute to the chemical defences that protect plants from insects, microbes and other potential threats.
Polygodial has been investigated as a fungal defence compound because of its antifungal activity. The relationship between its pungency and its ability to affect fungi helps explain why horopito has attracted research interest beyond its historical medicinal use.
However, a natural defensive function does not automatically make the compound suitable as a medicine. A substance can damage fungal cells while also irritating or otherwise affecting human tissues, depending on its concentration and how it is used.
This is one reason the chemistry of horopito needs to be considered alongside its safety profile.
What does horopito contain?
Horopito contains a range of naturally occurring compounds, with polygodial attracting particular interest because of its pungency and antifungal activity.
Polygodial
Polygodial is a bicyclic sesquiterpene dialdehyde isolated from the leaves of Pseudowintera colorata.
Its structure places it among a distinctive group of natural products found in certain members of the plant family Winteraceae. Researchers have investigated its effects on fungi, including Candida albicans, a yeast that can cause infections in humans.
Polygodial's biological activity is complex. Studies suggest that it can interfere with fungal cell membranes and disrupt important cellular functions.
The mechanism is relevant to understanding its activity, but it does not establish a safe and effective dose for treating an infection in a person. Laboratory concentrations may differ substantially from the concentrations achievable and tolerable in human tissues.
Other sesquiterpene compounds
Horopito leaves contain other specialised natural compounds, including related sesquiterpene dialdehydes.
Researchers have investigated these compounds because they may contribute to the plant's characteristic chemistry and biological activity. Their distribution and relative abundance can vary between species and preparations.
The overall activity of an extract cannot necessarily be attributed to polygodial alone. Other constituents, extraction methods and the concentration of the preparation may influence the results.
Flavonoids and other plant constituents
Chemical investigations of Pseudowintera species have also identified flavonoids and other compounds, particularly in work comparing leaves and fruits.
Flavonoids are widespread plant polyphenols that have attracted considerable research interest. However, their presence in horopito does not establish that an ordinary leaf preparation produces a particular antioxidant, anti-inflammatory or other clinical effect.
The chemistry of the whole plant is more complex than a list of individual compounds, and the biological relevance of each constituent depends on the preparation and the conditions being studied.
Why the species matters
The chemical composition of horopito is not interchangeable with that of every plant that shares its common name.
In particular, studies of polygodial in P. colorata should not be assumed to apply to P. axillaris. The two species have different chemical characteristics, and the early isolation of polygodial specifically from P. colorata was a key step in establishing its scientific interest.
This distinction is also relevant when buying commercial products. A label that simply says “native pepper tree” may not provide enough information to establish the exact species or chemical standardisation of the preparation.
What does modern research tell us?
Research into horopito spans several decades. Scientists have investigated its antifungal activity, the chemistry of polygodial and the potential applications of preparations derived from the plant.
The evidence needs to be interpreted in stages: identifying a compound, demonstrating activity in a laboratory and demonstrating safe clinical benefit in humans are different achievements.
Discovery of polygodial's antifungal activity
A landmark study published in 1982 investigated antibiotic substances in New Zealand plants and reported the isolation of polygodial from Pseudowintera colorata leaves.
The researchers identified polygodial as an agent with activity against Candida albicans.
This finding established a scientific basis for further investigation of horopito and its potential antifungal properties. It also helped explain why the plant had attracted interest in traditional and contemporary herbal practice.
However, an in-vitro result means that a compound has activity under laboratory conditions. It does not establish that chewing the leaves, drinking an infusion or applying an unstandardised extract will treat a fungal infection in a person.
The preparation, concentration, route of use, exposure time and site of infection all influence whether a laboratory result can translate into a useful treatment.
How polygodial may affect fungi
A 2001 study investigated the antifungal mechanism of polygodial.
The researchers found evidence that its activity involved disruption of fungal cell-membrane functions. The compound can interfere with the lipid and protein relationships that help maintain normal membrane function, affecting important processes within the cell.
This provides a plausible explanation for its antifungal action and helps distinguish the chemical's activity from that of compounds with different mechanisms.
Nevertheless, biological activity against fungi is only one part of the picture. The same reactivity that contributes to antifungal activity makes concentration, tissue compatibility and formulation important considerations.
A compound should not be described as a safe antifungal treatment merely because it inhibits fungal growth under experimental conditions.
Research involving recurrent vaginal candidiasis
There has been some human research involving a specific product containing horopito-derived oleoresin and polygodial.
Two studies published in 2011 and 2013 investigated a formulation known as K-712 in women with recurrent vulvovaginal candidiasis. The product contained oleoresin from Pseudowintera colorata, standardised to a stated polygodial concentration, alongside small amounts of olive-derived material.
The studies compared the product with the antifungal medicine itraconazole in a preventive treatment schedule.
This is important because it means the clinical evidence is not exclusively limited to laboratory experiments. However, the studies investigated a particular formulation, not raw horopito leaves, an ordinary tea or every supplement containing horopito.
A 2022 Cochrane review of treatments for recurrent vulvovaginal candidiasis assessed this evidence and judged it to be of very low certainty, citing serious concerns about study limitations and imprecision.
The review therefore does not provide reliable evidence that horopito products can be recommended as equivalent or superior to established antifungal treatment.
The findings warrant further investigation, but they should not be used to justify replacing prescribed treatment or self-treating recurrent symptoms without an appropriate diagnosis.
Antifungal activity beyond Candida
Researchers have investigated polygodial and related compounds against other fungi, and some studies have explored broader antimicrobial or biological effects.
Results vary by organism, compound and experimental method. It is important to report the specific organism and experimental setting rather than saying that horopito “kills all fungi” or is broadly effective against all infections.
Antifungal activity in a laboratory does not establish effectiveness against every fungal infection, and it does not show that an oral or topical botanical preparation will reach the relevant site at a suitable concentration.
What about antibacterial and antiviral claims?
Some commercial and herbal sources describe horopito as antibacterial or antiviral. These claims should be evaluated individually according to the evidence supporting each intended use.
Evidence that a particular compound has antifungal activity is not sufficient to conclude that it treats bacterial or viral infections.
For claims involving the whole plant, its products or a particular disease, the relevant preparation needs to be studied directly and appropriately.
The overall picture: Horopito has a well-established scientific interest as a source of polygodial, and its antifungal activity has been demonstrated in laboratory studies. Limited clinical research exists for a particular horopito-containing product, but the available clinical evidence remains too uncertain to establish a dependable treatment recommendation.
Traditional preparations and modern horopito products
Horopito has been described in historical sources as being chewed, steeped or prepared as a decoction or topical application.
These preparations should not be treated as equivalent to a standardised modern extract, because their composition and concentration may differ substantially.
Fresh and dried leaves
The leaves are the most frequently discussed plant part in relation to horopito's traditional use and modern chemistry.
Fresh leaves contain water and a mixture of natural constituents, while drying changes the water content and can influence the resulting preparation.
The pungency of the leaves is a useful characteristic, but it should not be used as a do-it-yourself measure of medicinal strength or safety. Avoid experimenting with raw-leaf ingestion or concentrated homemade preparations to treat an infection.
Water-based preparations
Historical accounts describe leaves being steeped in water or boiled to make a preparation.
A water-based preparation may extract a different group of compounds, and in different proportions, from an alcohol-based extract or an oleoresin.
The traditional use of a decoction is a valuable historical record, but it does not establish a modern dosage or a standardised level of polygodial. The strength of a homemade preparation may vary with plant identity, quantity, extraction time and storage.
Standardised extracts
Some commercial products use horopito-derived extracts or oleoresins that are characterised by their polygodial content.
Standardisation helps define the composition of a product, but it does not automatically establish clinical effectiveness. A standardised product still needs evidence for its intended route of use, condition and population.
The K-712 clinical research described above involved a specific combination product. Its findings should not be generalised to unrelated horopito extracts or supplements.
Topical products
Horopito-derived ingredients may be included in topical products because of their biological activity and historical association with skin complaints.
A properly formulated product is different from applying freshly chewed leaves or an improvised decoction. Concentration, stability, skin compatibility and manufacturing quality all matter.
Avoid applying homemade horopito preparations to broken skin, and do not use the plant as a substitute for medical treatment of an infected or worsening skin condition.
Growing horopito at home
Horopito is an attractive native shrub for suitable gardens, particularly where its colourful leaves can be appreciated throughout the year.
It naturally grows along forest margins and in shrubland, and established plants can tolerate considerable browsing by animals compared with some other native shrubs.
Growing conditions
Horopito generally suits a sheltered position with well-drained soil and light conditions that reflect its natural forest-margin habitat.
The foliage often develops more prominent red markings when exposed to brighter conditions, though leaf colouring is influenced by genetics, light, plant condition and the environment.
A position with some shelter from harsh conditions may help young plants establish. Avoid assuming that every cultivar has the same mature size, colour or growing requirements.
Propagation
Horopito can be grown from seed or propagated vegetatively, depending on the plant material and method used.
For home gardeners, a healthy plant from a reputable native nursery is often the simplest way to obtain the correct species. Check whether the plant is Pseudowintera colorata or another species in the genus.
Ecological value
Horopito contributes to native vegetation and can be useful in suitable restoration plantings. Its natural chemical defences help make it relatively unpalatable to some browsing animals, which can be useful in habitats where browsing pressure affects native regeneration.
Although the species is currently listed as Not Threatened, responsible collection still matters. A national conservation classification does not mean every local population should be harvested without consideration.
Growing horopito for its ornamental and ecological value is separate from using it medicinally. Garden plants may be exposed to sprays or other contaminants and should not automatically be considered suitable for making herbal products.
Harvesting and respecting native plant knowledge
Horopito is an indigenous taonga, and responsible harvesting should consider both the plant and the setting in which it grows.
Before collecting material, establish who owns the land, whether permission is required and whether any local rules or conservation concerns apply.
Because the common name horopito is used for related species, accurate identification is especially important when material is intended for research or medicinal purposes.
For scientific or commercial use, record the species, plant part, collection location, processing method and, where relevant, the chemical profile. These details make it easier to compare samples and understand variation.
In a rongoā Māori context, appropriate tikanga and guidance from knowledgeable practitioners should be respected. Historical written records do not necessarily contain the full cultural context of a plant's use, and practices may differ among iwi, hapū, whānau and practitioners.
Responsible use combines botanical accuracy, ecological stewardship and respect for the people and knowledge associated with the plant.
Safety considerations
Horopito's strong pungency is an important safety consideration. The plant should not be treated as harmless simply because it is native or has a history of traditional use.
Mouth and digestive irritation: Horopito leaves can cause a hot, burning sensation. Avoid experimenting with raw leaves or strong homemade preparations. Do not assume that a pungent plant will be soothing to the digestive tract.
Gastritis and peptic ulcers: Because of its pungency and limited safety evidence, medicinal horopito preparations are best avoided in people with active gastritis or peptic ulcer disease unless specifically advised by an appropriately qualified health professional.
Skin use: Do not apply fresh, chewed or concentrated horopito preparations to broken skin or serious wounds. Irritation is possible, and a homemade preparation is not sterile.
Fungal infections: Do not substitute horopito for established antifungal treatment without medical guidance. Persistent or recurrent infections require proper diagnosis, as different conditions can produce similar symptoms and may need different treatments.
Pregnancy and breastfeeding: Reliable safety data for medicinal horopito preparations are limited. Avoid medicinal use during pregnancy or breastfeeding unless advised by an appropriate health professional.
Children: Do not give children raw horopito leaves or homemade medicinal preparations based on historical recipes. There is insufficient reliable information to establish suitable paediatric doses.
Medicines and health conditions: Clinical interaction data remain limited. If you take regular medicines or have an ongoing health condition, discuss a specific horopito product with a qualified health professional or pharmacist.
Allergy or adverse reaction: Stop using a product if it causes significant burning, irritation, rash or other unexpected symptoms. Seek urgent care for serious or rapidly worsening reactions.
Quality and concentration: A standardised commercial extract is not equivalent to raw leaves, a homemade decoction or another brand's formulation. Follow product-specific directions and avoid taking concentrated preparations by a route for which they were not designed.
The absence of comprehensive safety data is not proof that every horopito product is dangerous. It does, however, mean that dosage, suitability and risk need to be assessed carefully rather than inferred from traditional use alone.
Understanding horopito's place in modern herbal practice
Horopito demonstrates how traditional knowledge can prompt scientific questions without automatically providing all the answers.
Historical accounts document its use for skin complaints, stomach pain and toothache. Modern phytochemistry has identified polygodial, while laboratory studies have demonstrated antifungal activity and investigated how the compound may affect fungal cell membranes.
A small body of clinical research has also examined one defined horopito-containing product for recurrent vaginal candidiasis. However, systematic review evidence has judged the certainty of those clinical findings to be very low.
These different kinds of evidence should not be blended into a single broad claim that horopito is proven to treat fungal disease.
A responsible herbal approach asks which species was studied, which preparation was tested, what dose was used, what outcomes were measured and whether the findings can reasonably be applied to the product under consideration.
Horopito remains a fascinating native plant, with a distinctive chemistry and a meaningful place in Aotearoa's ethnobotanical history. Its potential is best explored through accurate identification, appropriate safety assessment and well-designed research.
In summary
Horopito (Pseudowintera colorata), also known as red horopito or mountain horopito, is an endemic New Zealand shrub recognised by its red-blotched leaves and pronounced peppery taste.
Historical accounts associate horopito with traditional uses for skin complaints, stomach pain and toothache. However, some records use the name broadly enough that the exact species involved cannot always be confirmed.
Modern scientific research has isolated polygodial from the leaves and demonstrated antifungal activity in laboratory experiments. Limited human studies have examined a specific horopito-containing product for recurrent vaginal candidiasis, but a Cochrane review judged the evidence to be of very low certainty.
Horopito should therefore be understood as a scientifically interesting native plant with promising preclinical findings, rather than a proven treatment for every fungal infection. Its pungent chemistry also makes correct formulation and careful use important.
A thoughtful approach respects rongoā Māori, recognises the limits of the current evidence and avoids treating a plant's natural origin as a guarantee of safety.
Sources and further reading
1. New Zealand Plant Conservation Network. Pseudowintera colorata — botanical identification, distribution, habitat, leaf features and conservation status. https://www.nzpcn.org.nz/flora/species/pseudowintera-colorata/ 2. Manaaki Whenua – Landcare Research, Ngā Rauropi Whakaoranga. Pseudowintera colorata. Horopito. Pepper tree. Historical ethnobotanical records, species-identification caveats and details of reported traditional uses. https://rauropiwhakaoranga.landcareresearch.co.nz/names/4be0bbe7-37ab-488d-a594-9638581bb4f1 3. McCallion, R. F., Cole, A. L. J., Walker, J. R. L., Blunt, J. W. and Munro, M. H. G. (1982). “Antibiotic substances from New Zealand plants. II. Polygodial, an anti-Candida agent from Pseudowintera colorata.” Planta Medica, 44(3), 134–138. https://doi.org/10.1055/s-2007-971422 4. Kubo, I., Fujita, K. and Lee, S. H. (2001). “Antifungal mechanism of polygodial.” Journal of Agricultural and Food Chemistry, 49(3), 1607–1611. Research into how polygodial affects fungal cell-membrane function. https://doi.org/10.1021/jf000136g 5. Kumari, A. et al. (2011). “Protective effect of an oral natural phytonutrient in recurrent vulvovaginal candidiasis: a 12-month study.” Journal of Biological Regulators and Homeostatic Agents, 25(4), 543–551. https://pubmed.ncbi.nlm.nih.gov/22217987/ 6. Chopra, V. et al. (2013). “Prophylactic strategies in recurrent vulvovaginal candidiasis: a 2-year study testing a phytonutrient vs itraconazole.” Clinical investigation of a defined horopito-containing combination product. https://pubmed.ncbi.nlm.nih.gov/24152852/ 7. Cooke, G. et al. (2022). “Treatment for recurrent vulvovaginal candidiasis.” Cochrane Database of Systematic Reviews. The review assesses the relevant clinical evidence as very low certainty. https://doi.org/10.1002/14651858.CD009151.pub2 8. Te Ara – The Encyclopedia of New Zealand. Rongoā: medicinal use of plants. Background on traditional Māori plant knowledge and its wider cultural context. https://teara.govt.nz/en/rongoa-medicinal-use-of-plants This guide is educational and is not a substitute for individual medical advice or guidance from a qualified rongoā Māori practitioner.