Piper excelsum: kawakawa

Piper excelsum, otherwise known as kawakawa, is a New Zealand native that is widely distributed throughout both islands. It grows as a small shrub or tree, reaching heights of up to 5 metres. The dark green leaves are often punctured with holes made by the kawakawa looper moth. Kawakawa produces flowers on erect, green spikes which, after pollination, develop into small, berry-like fruits. These fruits are eaten by native birds, particularly the kererū.

The leaves, bark and roots of kawakawa have traditionally been used by Māori for a variety of purposes, including soothing toothaches, treating skin problems, easing joint discomfort and aiding digestion. The undersides of the leaves were used as a poultice for cuts, abrasions and other skin problems. To help soothe a toothache, the leaves were chewed, while leaves were also chewed and swallowed to help ease digestive discomfort. For joint discomfort, the leaves were traditionally applied topically to the affected area.

Researchers at the University of Auckland have identified several compounds in kawakawa that may help explain some of the biological effects traditionally associated with the plant. One of the most abundant compounds identified was pellitorine, a bioactive compound that has been studied for its effects on sensation and inflammation. Another compound found in kawakawa is yangambin, which has also been investigated for its anti-inflammatory properties. While these findings provide interesting insights into the chemistry of kawakawa, further research is needed to establish how these compounds affect human health in practice.

Kawakawa leaves can traditionally be prepared as a tea by rinsing fresh leaves and steeping them in hot water before straining and serving. For topical use, fresh leaves have traditionally been crushed or chewed before being applied to the affected area. Kawakawa leaves can also be infused into a carrier oil, such as olive oil, for topical application. A range of kawakawa-based topical products are also available commercially.

If you are considering using kawakawa to address a medical problem, particularly if you have an existing condition or are taking medication, consult a doctor or other qualified healthcare professional first.