The siwak is a stick cut from the arak tree. It is used to clean the mouth and teeth, to perfume the mouth and to remove bad smells. It is a confirmed Sunnah of the Prophet (blessings and peace of Allah be upon him), and he would enjoin people to use it. It is cleansing for the mouth and pleasing to the Lord, as the Prophet (blessings and peace of Allah be upon him) said. This hadith highlights how extensively the Prophet (blessings and peace of Allah be upon him) would clean his mouth with the siwak, as Abu Musa al-Ash‘ari (may Allah be pleased with him) narrates that the Prophet (blessings and peace of Allah be upon him) was cleaning his teeth with a siwak, reaching to the furthest part of the throat, to the extent that he made a sound as if he were going to vomit, saying “Agh, agh.” This is describing the sound made when he using the siwak, because of how extensively he was cleaning his teeth and mouth with it. This hadith highlights the virtue and importance of the siwak..