The siwāk or miswāk (pi. masāwīk) isoften mentioned as a symbol for the emphasis givenin medieval Islam to dental health. Although notmentioned in the Qur'ān—the prime source oflegitimacy in Islam—the siwāk gained popularitythrough being attributed to the daily practice ofthe Prophet Muhammad whose advanced understanding ofpreventive dentistry is lauded as being only part ofhis general concern with preventive medicine. Evenon his death bed the Prophet is said not to havegiven up the use of the siwāk, since he alwaysordered Muslims to “purify your mouths for they arethe channels through which utterances of praise toGod (subḥāna Allāh) travel”. Theword siwāk derives from the Arabic rootswk, which indicates rubbing forthe purpose of cleaning. Hence siwāk or miswāk arethe names of the wooden instrument which has beenused as a “tooth-stick”(Zahnstocher), or as an earlyform of the toothbrush, to clean the teeth anddeodorize the mouth. The siwak is a wooden stickabout 8 inches long and as wide as a finger. Theedge is usually chewed so that the fibres separateto become like a brush. In contemporary Islamicethics, of which the fatāwāliterature (legal responsa) is only one example, thesiwāk has regained recognition and is often praisedas the preferred means for dental care.