Kumerahou is a branching shrub growing up to 3 metres high, found in the top half of the North Island of Aotearoa. Its name probably derives from its attractive creamy yellow flowers appearing in early spring to mark the coming of the kumara planting season. Once commonly found on roadsides and in poor, clay soils (hence one of its names, “Poverty weed”), it is becoming less widespread as human activity encroaches more and more on its traditional habitat.
Flavonoids, including the flavonols quercetin & kaempferol, highest levels of which occur in the flowers, ellagic acid & its 0-methyl ethers, saponins, iron.
Unfortunately, like most of our native plants, very little scientific investigation has been conducted into the possible pharmacological actions of Kumerahou. Nevertheless, this plant has a strong reputation for the treatment of several conditions, in particular those affecting the lungs. Most of the following is derived from ethnobotanical information on traditional or folklore usage, as opposed to that published in scientific journals.
Expectorant – helps to remove excess mucus from the respiratory system.
Alterative – helps restore normal body functions by improving the removal of metabolic wastes.
Antidyspeptic – helps relieve indigestion.
Antirheumatic – helps relieve and prevent rheumatic conditions and gout.
Vulnerary – soothes and aids the body in the healing process.
The leaves and flowers of Kumerahou were used as a poultice on or to bathe wounds, sores and rashes. Liquid made from Kumerahou was also used in the bath, not only as a soap substitute, but also for its soothing emollient properties probably due also largely to saponins. An ointment made from Kumerahou was sold in Auckland many years ago for skin cancer. No further information is available on this, and a proper investigation into this possible activity would certainly be useful.
No significant adverse effects have been reported to date, either from internal or external use of Kumerahou preparations. Like other saponin-rich plants, however, the ingestion of excessive doses or even moderate doses in a few sensitive individuals, may result in emesis or vomiting.
20 – 40ml per week of a 1:2 fluid extract. (available by prescription through a Registered Medical Herbalist)
Phytomed Medicinal Herbs Ltd – Phil Rasmussen
Maori Healing and Herbal by Murdoch Riley