Pseudowintera colorata is a species of small, woody evergreen flowering shrub part of family Winteraceae. The species is endemic to much of New Zealand. It is abundant in upland and mountain forests in the North Island and extends down to sea level. It grows up to eight metres in height. The upper surface of its light-green, elliptical leaves is often splotched with red, especially if the plant is exposed to sunlight. The leaves undersides are a blue-grey colour.

Tiny greenish-white flowers appear in early spring, followed by black berries in autumn. The berries are very palatable to birds. Pseudowintera colorata is continually exposed to attack by various insects and parasites and its occurrence in high rainfall areas makes it particularly susceptible to attack by fungi. This has led to efficient built-in defence mechanism of a compound called Sesquiterpene dialdehyde polygodiali which has anti-fungal properties. Pseudowintera colorata leaves and an extract from the leaves are now used in a number of commercial antifungal products based on the results of scientific research. The characteristically sharp, hot peppery taste of a leaf when chewed is primarily due to these polygodial compounds which cause pungency on the tongue in concentrations as low as 0.1 µg. Ground up leaves are used as a condiment in ethnic foods. As the leaves taste bad to deer and stock and are not eaten, this shrub often dominates the understorey vegetation in heavily browsed forests.

Maori uses Horopito has long been used by the indigenous Maori population of New Zealand both internally and externally for many purposes. As far back as 1848, Horopito is documented in the treatment of skin diseases such as ringworm, or for venereal diseases. “The leaves and tender branches of this shrub are bruised and steeped in water, and the lotion used for ringworm; or the bruised leaves are used as a poultice for chaffing of the skin, or to heal wounds, bruises or cuts”. Infection due to Candida albicans (Maori – Haha, Haka) is documented as being a major cause of death of Maori babies, due to their being fed an “unsatisfactory diet.” The juice of Horopito leaves was placed straight in the mouth, or alternatively, leaves were steeped in water to extract the juice and this decoction was used in the treatment of what we now understand as oral thrush (candidiasis). Early European settlers to New Zealand also used Horopito for medicinal purposes. For internal use, leaves were either chewed or prepared as a tea. “The leaves and bark are aromatic and pungent; the former is occasionally used by settlers suffering from diarrhoeic complaints.” A decoction of the leaves was taken for stomach ache and was known as “Maori Painkiller” and “Bushman’s Painkiller.” There are accounts of the bark being used in the 19th century as a substitute for quinine: “The stimulating tonic and astringent properties of which are little inferior to winter’s bark.”. A French nun, Mother Aubert, went to live among the Maori at the end of the 19th century, and the native plant remedies she later created became commercially available and widely used throughout the colony of New Zealand. Horopito was one of the two ingredients in her patent medicine, Karana. In a letter to the French Consul dated 2 December 1890, she described it as “superior to Quinquina [quinine] in the treatment of chronic stomach sickness. It has been very useful to me in cases of anaemia of debility, of continuous diarrhoea etc and in recovery from temperatures”.