Spilanthes acmella Seeds | Toothache Plant
LATIN NAME: Spilanthes acmella
COMMON NAME: Toothache Plant
Plant Profile
The toothache plant is a low, spreading annual of the daisy family, native to the Amazon basin and now grown throughout the tropics. It grows twenty to forty centimetres tall and spreads to twice that, with opposite, ovate, toothed leaves and a prostrate habit that roots where the stems touch the ground.
The flower heads are the reason it is grown: they are cone-shaped, yellow with a dark red centre, and they look like a small, domed button or a fried egg, hence the name buzz buttons. Chewing one produces a strong tingling, numbing sensation followed by a burst of saliva, which lasts a few minutes. The plant flowers from midsummer until the frost.
Science & Biotechnology
The active compound is spilanthol, an N-alkylamide that binds to the same receptors as the local anaesthetics and produces a tingling, numbing effect on the mouth. The genus has been revised, and the plant long grown as Spilanthes acmella is now usually placed in Acmella oleracea, with the name Spilanthes acmella reserved for a related species; the nursery trade has not caught up with the change.
Spilanthol is extracted commercially and used in oral care products and in a cosmetic preparation marketed for facial wrinkles, where it is claimed to relax the underlying muscle. The evidence for the cosmetic use is limited to small studies. The plant also contains eudesmanolide lactones, and the leaves are rich in vitamin C and in iron, which is part of why they are eaten as a vegetable in Brazil.
Uses & Benefits
The flower heads are chewed for toothache and for mouth ulcers, and a tincture is used as a gargle; the numbing effect is real but temporary, and it is not a substitute for dental treatment. In Brazil and in Southeast Asia the young leaves are eaten raw in salads and in soups, where they add a peppery, slightly numbing note, and the leaves are cooked with fish.
The plant is also grown as an ornamental for its curious flowers, in a pot or at the front of a warm border, and it is a good subject for a child’s garden because the effect is so immediate. It is used in traditional medicine across the tropics for malaria, for sore throat and for skin infections, though the clinical evidence is thin. The plant is not frost-hardy and is grown as an annual in temperate gardens.
Growing from Seed
Sow in late winter at 20-24 °C on the surface of a moist compost, pressed in but not covered, since the seed needs light. Germination takes two to three weeks and is usually reliable. Prick the seedlings out when they are large enough to handle and grow them on warm and bright; they are fast-growing and can be planted out six weeks after sowing.
Plant out after the last frost, in full sun, in rich, moist, well-drained soil, and space them 30 centimetres apart, since the plants spread. Water regularly, and pinch the tips once to make them bushier. The flower heads are best harvested when the centre is still yellow, before it turns dark red, and the plant will keep producing until the frost. Save seed from the earliest heads, since later seed may not ripen in a short season.
Our Take
A curiosity with a genuine numbing effect, and a salad herb in its native range. Grow it in a pot and let people try a flower.
Related Reading
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