The “toothache plant,” scientifically known as Acmella oleracea, is a flowering herb native to the tropics. Historically utilized as a traditional herbal remedy across South America, Africa, and Asia, it is primarily recognized for the distinct, temporary numbing sensation it produces when its fresh parts are chewed. This effect has made it a subject of increasing modern scientific interest for its potential pain-relieving properties.
Botanical Identity and Appearance
This herbaceous plant belongs to the Asteraceae family, which also includes common daisies and sunflowers. Acmella oleracea grows as a bushy, low-lying perennial in warmer climates, though it is often cultivated as an annual in temperate regions. The plant is known by a variety of vivid common names that reflect its effects and appearance, such as Paracress, Buzz Buttons, and Electric Daisy.
The plant’s most distinctive feature is its small, cone-shaped inflorescences, or flower heads. These flowers are typically golden yellow, sometimes featuring a reddish-brown tip that leads to the nickname “Eyeball Plant.” The leaves are ovate to triangular with toothed margins and are used medicinally and in cooking.
The Mechanism of Pain Relief
The unusual physical sensation produced by the toothache plant is caused by a potent natural compound called spilanthol. Spilanthol is an isobutyl amide, a type of organic molecule that acts as a local anesthetic. When the plant material is chewed, spilanthol is released and interacts rapidly with sensory nerve endings in the mouth.
This interaction causes the immediate, intense tingling and buzzing feeling that precedes the numbing effect. The mechanism is thought to involve the modulation of specific ion channels in nerve cells, particularly the voltage-gated sodium (Na+) channels. By influencing these channels, spilanthol essentially interrupts the transmission of pain signals to the brain, producing a noticeable anesthetic effect.
Spilanthol also stimulates the salivary glands significantly, increasing the flow of saliva. This dual action of numbing and salivation has made the plant a valuable traditional remedy for various oral discomforts. The anesthetic effect is temporary but provides a rapid onset of relief.
Practical Applications and Preparation
Historically, the most widespread use of Acmella oleracea has been in folk medicine for treating various oral ailments. Traditional preparation often involves simply chewing a small piece of the fresh flower or leaf. This method delivers a concentrated dose of spilanthol directly to the affected area, providing quick, topical pain relief for conditions like toothaches, gum infections, and sore throats.
Beyond medicinal uses, the plant is also a unique culinary ingredient, particularly in northern Brazil, where it is known as Jambu. Fresh leaves are sometimes added to salads to impart a subtle, pungent flavor and the signature tingling sensation. When cooked, the leaves lose their strong flavor and can be consumed as a leafy green vegetable.
The concentrated extracts of the plant are now used commercially in various oral care products, including dentifrices and mouthwashes. These extracts harness the numbing, analgesic, and antimicrobial properties of spilanthol for broader oral hygiene applications. The unique sensory experience has also led to its incorporation into certain drinks and cocktails as a novel flavor enhancer.
Important Safety Considerations
While the toothache plant has a long history of traditional use, it is important to approach consumption with caution and not as a substitute for professional medical care. The plant possesses diuretic activity, meaning it may increase urination. Individuals taking prescription diuretic medications should consult a healthcare provider before use, as the combined effect could lead to dehydration or electrolyte imbalance.
As with many herbal remedies, scientific data on long-term safety and interactions in humans are limited. Due to its anti-inflammatory and analgesic properties, the plant could theoretically interact with blood-thinning medications. Therefore, people on anticoagulants should avoid it unless cleared by a physician. Individuals with known allergies to plants in the Asteraceae family should also avoid the toothache plant.
Because of the lack of comprehensive human clinical trials, the use of Acmella oleracea is generally not recommended during pregnancy or breastfeeding. It is always best to start with a very small amount to assess sensitivity, and any severe or persistent pain should always prompt a visit to a dental professional.