Salvadora persica (toothbrush tree)
An evergreen shrub or tree from tropical Africa to Asia, toothbrush tree has a wide range of uses, including the chewing of its twigs to promote dental hygiene.
Illustration of Salvadora persica by William Roxburgh, from Plants of the Coast of Coromandel (1793)
Salvadora persica L.
toothbrush tree (English); aarak, arak, arrak, arraka, el rak, kabats, shaow, shau, siwak (Arabic)
Not assessed according to IUCN Red List criteria, but not considered to be threatened.
Thorny scrub or grassland, along river banks or on seasonal floodplains; also along the coast.
Food and drink, medicine.
About this species
Toothbrush tree is a small, evergreen shrub or tree that grows in hot, dry conditions in parts of Africa, the Middle East and the Arabian Peninsula. It is valued as a medicinal plant by local people, since it contains a number of active compounds that promote good health.
As the common name suggests, small stems and roots are used as chewing sticks or natural toothbrushes and have been shown to reduce tooth decay, plaque and gum disease.
Although the flowers are small and inconspicuous, the fruits that follow can be eaten or made into a drink, and the seeds are a valuable source of oil.
Embelia grossularia Retz., Galenia asiatica Burm.f.
Geography and distribution
Salvadora persica is native to the Arabian Peninsula, Africa, western Asia, the Middle East, India, Pakistan and Sri Lanka.
Although it is drought tolerant, toothbrush tree is often found where there is some ground water. It is also salt tolerant, growing along coasts or on saline soils.
Overview: An evergreen shrub or small tree, reaching up to 7 m tall, with many drooping branches.
Leaves: Rounded to ovate, slightly fleshy, about 7 × 3 cm, arranged in opposite pairs.
Flowers: Small, greenish, arranged in loose panicles up to 30 cm long.
Fruits: Fleshy berries about 1 cm in diameter, becoming red-scarlet when ripe. Each contains a single seed.
Other common names
Other common names for this species include: aarak, arak, arrak, arraka, el rak, kabats, shaow, shau, siwak (Arabic); jhal (Bengali); jhak, kharjal (Hindi); msuake, mswaki, musuake (Swahili); kalawa, karkol, perungoli, ughaiputtai, vivay (Tamil).
Threats and conservation
Although Salvadora persica has a wide distribution and tolerates harsh conditions, it is vulnerable to habitat loss and overgrazing.
Food and drink
Toothbrush tree fruit can be eaten fresh, cooked, dried and stored or made into a fermented drink. The leaves have a bitter, peppery taste and are eaten as a green vegetable or made into a sauce.
Medicine and hygiene
The most widespread use of toothbrush tree is for chewing sticks or natural toothbrushes. Small twigs (around 3-5 mm in diameter) are used and have both physical and anti-microbial action, helping to control plaque and prevent tooth decay.
Roots and stems contain numerous active compounds, including salvadorine and benzylisothiocyanate, which inhibit bacteria that cause tooth decay, and tannins, which reduce plaque and gum disease. Leaves can be made into a mouthwash with similar properties.
Chewing sticks have been used for dental hygiene as far back as the time of the Babylonians (around 7000 BC). Salvadora persica is mentioned in the Qur’an and the Bible (as ‘mustard seed’ or ‘pepper bush’). Today, it is used as a natural toothbrush by millions of people.
Other parts of the toothbrush tree are used to treat a range of ailments, including stomach ache, rheumatism and sores.
Household cleaning products
When pressed, seeds yield oil that is rich in lauric and myristic acids and can replace coconut oil in production of soaps and detergents.
Shelter and land-reclamation
Being tough and resilient to harsh conditions, toothbrush tree is often planted as a windbreak and can be used to improve saline or impoverished soils.
Leaves of Salvadora persica are browsed by cattle, sheep, goats and camels, although they are said to make milk taste bad. The flowers are a useful source of nectar for honeybees.
Millennium Seed Bank: Seed storage
The Millennium Seed Bank Partnership aims to save plant life worldwide, focusing on plants under threat and those of most use in the future. Seeds are dried, packaged and stored at a sub-zero temperature in our seed bank vault.
Five collections of Salvadora persica seeds are held in Kew’s Millennium Seed Bank based at Wakehurst in West Sussex.
Toothbrush tree is usually harvested from the wild rather than being cultivated. However, it germinates easily from seed once the flesh of the fruit is cleaned away and coppices well.
It tolerates extreme heat (up to about 45 ⁰C) and drought, but production is higher when it has some moisture around the roots.
This species at Kew
Toothbrush tree can be seen growing in Kew’s Palm House, where it is located in the African section (bed 17).
Dried and spirit-preserved specimens of Salvadora persica are held in Kew’s Herbarium where they are available to researchers by appointment. The details of some of these specimens, including images, can be seen online in Kew’s Herbarium Catalogue.
Specimens of stems, roots, seeds, wood, bark and fruits of toothbrush tree, as well as chewing sticks and toothpaste made from it, are held in Kew’s Economic Botany Collection in the Sir Joseph Banks Building, where they are available to researchers by appointment.
Toothpaste made from Salvadora persica is displayed in the Plants+People exhibition, in Kew’s Museum No. 1.
Al Sadhan, R. I. & Almas, K. (1999). Miswak (chewing stick): a cultural and scientific heritage. The Saudi Dental Journal 11: 80–88.
Ghazanfar, S. A. (2011). Medicinal plants of the Middle East. In: Genetic Resources, Chromosome Engineering and Crop Improvement, ed. Ram J. Singh, pp. 163–180, CRC Press, Florida, USA.
Paull, R. E. (2008). Salvadora persica. In: The Encyclopedia of Fruit and Nuts, ed. J. Janick & R. E. Paull, pp. 791–792, CABI International, Wallingford, UK.
Sher, H., Al-Yemeni, M. N., Masrahi, Y. S. & Shah, A. H. (2010). Ethnomedicinal and ethnoecological evaluation of Salvadora persica L.: a threatened medicinal plant in Arabian Peninsula. Journal of Medicinal Plants Research 4: 1209–1215.
World Agroforestry Centre (2013). Salvadora persica, Agroforestree database. Available online.
Kew science editors: Beccy Middleton and Shahina Ghazanfar
Kew contributor: Scott Taylor
Copyediting: Emma Tredwell
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