Toothache Plant

Acmella oleracea, known as the toothache plant or Szechuan buttons, is a fast-growing annual herb from Brazil in the daisy family. Its small gold and red flower heads contain spilanthol, a compound that produces an intense tingling, numbing sensation on contact with the mouth. The whole plant is edible, and the flowers are especially prized as a culinary curiosity. It is frost-sensitive and thrives in warm, sheltered conditions.

Growing

Start seeds indoors when indoor temperatures are stable above 20 °C, approximately 8 weeks before outdoor nights stay reliably above 15 °C. Sow seeds shallowly, pressing them to within 2–3 mm of the surface — light aids germination. Keep the growing medium evenly moist at 20–25 °C; seedlings emerge in 7–14 days. Pot on into 10–12 cm containers once the first true leaves appear. Harden off gradually before moving plants outdoors. Space final plants 30 cm apart in containers or sheltered beds.

Care

Water regularly to keep soil evenly moist but never waterlogged; drought causes premature flowering and reduces vegetative vigour. Feed with a balanced liquid fertiliser every 2 weeks once established. Pinch out the growing tips early to encourage bushy branching. Remove spent flowers promptly to extend the harvest period. In Sweden, grow in pots outdoors in a sheltered spot, or in a greenhouse or conservatory, as the plant cannot tolerate frost.

Harvest

Harvest flower buds and open flowers as soon as they reach full colour — typically from about 90 days after sowing. Pick individual buds or snip whole flower heads with scissors. Young leaves can be harvested throughout the growing period. Harvest regularly to keep the plant productive; the harvest window can extend up to 60 days with consistent picking.

In the kitchen

Use fresh flower buds whole as a dramatic table garnish with sparkling wine, or scatter over dishes as a tingling, effervescent topping. Chew fresh leaves for their numbing, antibacterial properties — the traditional use against toothache. The flowers pair well with seafood, cocktails, and fermented foods. Use in small quantities, as the numbing effect is potent.

Storing

Use flower buds and leaves immediately after harvest for maximum effect. If needed, keep freshly picked flowers in a sealed container in the refrigerator for up to 2 days. Do not freeze, as freezing destroys both texture and the active spilanthol compounds.