The miswak (miswaak, siwak, sewak, Arabic: سواك or مسواك) is a teeth cleaning twig made from the Salvadora persica tree (known as arāk, أراك, in Arabic). It is reputed to have been used over 7000 years ago. The miswak's properties have been described thus: 'Apart from their antibacterial activity which may help control the formation and activity of dental plaque, they can be used effectively as a natural toothbrush for teeth cleaning. Such sticks are effective, inexpensive, common, available, and contain many medical properties'. It also features prominently in Islamic hygienical jurisprudence.The World Health Organization (WHO) recommended the use of the miswak in 1986, but in 2000 an international consensus report on oral hygiene concluded that further research was needed to document the effect of the miswak. Some of this further research has been done on a population of 203, and concluded, in turn, 'that the periodontal status of miswak users in this Sudanese population is better than that of toothbrush users'. Yet another comparative study conducted on a sampling of 480 Saudi Arabian adults found that 'the level of need for periodontal care in the sample chosen is low when compared with the findings of similar studies undertaken in other countries. The frequent use of the 'Miswak' was associated with a lower need for treatment'.Mouthrinses containing chlorhexidine was with maximum antibacterial activity, while cetylpyridinium chloride mouthrinses were with moderate and miswak extract was with low antibacterial activity.The use of the miswak is frequently advocated in the hadith (the traditions relating to the life of Muhammad). Situations where the miswak is recommended to be used include before religious practice, before entering one's house, before and after going on a journey, on Fridays, before sleeping and after waking up, when experiencing hunger or thirst and before entering any good gathering.Were it not that I might over-burden the Believers I would have ordered them to use Siwak (Miswak) at the time of every Prayer.Four things are from among the practices of the Prophets: Circumcision, Perfume, Miswak, and Marriage.Make a regular practice of Miswak for verily it is the purification for the mouth and a means of the pleasure of the Lord.Use the Miswaak, for verily, it purifies the mouth, and it is a Pleasure for the Lord. Jib-ra-eel (A.S.) exhorted me so much to use the Miswaak that I feared that its use would be decreed obligatory upon me and upon my Ummah. If I did not fear imposing hardship on my Ummah I would have made its use obligatory upon my people. Verily, I use the Miswaak so much that I fear the front part of my mouth being peeled (by constant and abundant brushing with the Miswaak)A miswak should be one hand span in length when selected. If it becomes dry, it should be soaked in any water to soften the end bristles. The end should be cut afresh to ensure hygiene and should never be stored near a toilet or sink. The brush may be created by cutting Salvadora persica's branches instead of its roots; keeping in mind that the tree's roots can retain moisture more so than its branches. This favors more long-term usage.Many companies offer special cases for carrying miswak. Many of these companies also produce miswak itself. The main purpose of these cases is to protect and carry miswak in order to preserve its freshness. Plastic toothbrush cases are available at most drug stores and may be used for carrying a Miswak.