Salvadora persica (arak, jhak, p?lu, Salvadora indica, toothbrush tree, mustard tree), is a species of Salvadora. Used for centuries as a natural toothbrush, its fibrous branches have been mentioned by the World Health Organization for oral hygiene use.
Salvadora persica is a small tree or shrub with a crooked trunk, typically 6-7 metres (20-23 ft) in height. Its bark is scabrous and cracked, whitish with pendulous extremities. The root bark of the tree is similar in colour to sand, and the inner surfaces are an even lighter shade of brown. It has a pleasant fragrance, of cress or mustard, as well as a warm and pungent taste. The leaves break with a fine crisp crackle when trodden on. The tree produces small red edible fruits, juicy but pungent, in clusters.
Salvadora persica stick, known as miswak, is popular for teeth cleaning throughout the Arabian Peninsula, as well as the wider Muslim world. The fresh leaves can be eaten as part of a salad and are used in traditional medicine. The flowers are small and fragrant and are used as a stimulant and are mildly purgative. The berries are small and barely noticeable; they are eaten both fresh and dried. The wood of the Salvadora persica can be used for charcoal and firewood. In Namibia, the mustard bush is used as drought-resistant fodder for cattle. The seeds can be used to extract a detergent oil.