Praise be to Allah.
Siwaak means cleaning the mouth and teeth with a siwaak, which is the name given to the tool used. The siwaak is a stick or twig used for this purpose.
Siwaak is a method of cleaning the mouth which also earns the pleasure of Allaah, as is proven in the hadeeth of Aaishah (may Allaah be pleased with her) who said: The Messenger of Allaah (peace and blessings of Allaah be upon him) said, Siwaak cleanses the mouth and pleases the Lord.(Reported by [??] al-Bukhaari in his Saheeh, 2/274, and by [??] Ahmad, 6/47, and al-Nisaai, 1/50. Its isnaad is saheeh, see al-Irwa 1/105).
Use of the siwaak is repeatedly encouraged, as in the hadeeth of Abu Hurayrah (may Allaah be pleased with him), who reported that the Prophet (peace and blessings of Allaah be upon him) said: Were it not for the fact that I did not want to make things too hard for my ummah, I would have commanded them to use the siwaak at every time of prayer.(Reported by al-Bukhaari, 2/299 and Muslim, 1/151). According to another report narrated by al-Bukhaari, he said: at every time of making wudoo.
Imaam al-Nawawi reported that the respectable scholars were agreed that use of the siwaak is sunnah and is encouraged. One of the signs of its importance is the fact that some of the salaf (early generations of Islam), such as Ishaaq ibn Raahawayh, thought that it was obligatory.
Times when use of siwaak is recommended
Siwaak is recommended at all times of night and day, because of the general sense of the hadeeth quoted above from Aaishah, Siwaak cleanses the mouth and pleases the Lord. The scholars have also mentioned situations where use of the siwaak is even more strongly encouraged. These include:
When making wudoo and at times of prayer.The Prophet (peace and blessings of Allaah be upon him) said: Were it not for the fact that I did not want to make things too hard for my ummah, I would have commanded them to use the siwaak at every time of prayer. According to another report he said: at every time of making wudoo as already stated above.
When entering one's home to be with ones family.Aaishah was asked what the Messenger of Allaah (peace and blessings of Allaah be upon him) did when he first came home. She said, When he entered his house, the first thing he would do was to use the siwaak.
When getting up from sleep. Hudhayfah ibn al-Yamaan (may Allaah be pleased with him) reported that when the Prophet (peace and blessings of Allaah be upon him) got up during the night, he would clean his mouth thoroughly with the siwaak. (Reported by al-Bukhaari, 1/98 and Muslim, 1/220)
When the smell of ones mouth changes, whether this is because of eating food with a strong odour, or because of not eating or drinking for a long time, etc. Siwaak is cleansing for the mouth, which means that it should definitely be used when the mouth needs cleaning.
When going to the mosque. Using siwaak is part of the adornment which we are commanded to wear for every prayer, as Allaah says (interpretation of the meaning): O Children of Aadam! Take your adornment while praying [al-Araaf 7:31]. It is also important because the angels are present in the mosque, and one is going to meet with other worshippers there.
When reading Quraan and joining gatherings in which Allaah is remembered (dhikr), because the angels are present on such occasions.
Using siwaak when fasting
The scholars (may Allaah have mercy on them) are agreed that there is nothing wrong with using siwaak during the day when one is fasting, but they differed with regard to using it after noon, which some of them disliked (regarded as makrooh). The correct view is that it is sunnah for one who is fasting, just as it is for anyone else, because of the general sense of the reports which prove that it is sunnah. The Prophet (peace and blessings of Allaah be upon him) did not make any exceptions or state any specific time, and a statement that is general in nature should continue to be taken as general unless there is evidence to indicate that it is specific in application. The hadeeth used as evidence to forbid using siwaak after noon is attributed to Ali ibn Abi Taalib (may Allaah be pleased with him), who is quoted as saying that the Prophet (peace and blessings of Allaah be upon him) said, When you fast, use siwaak in the morning but do not use it in the afternoon.(Reported by al-Daaraqutni. This is a daeef (weak) hadeeth. Ibn Hajar said, in al-Talkhees al-Habeer, 1/62: a daeef (weak) isnaad). There is no proof that this can be attributed to the Prophet (peace and blessings of Allaah be upon him). With regard to the use of the hadeeth The odour that comes from the mouth of the fasting person is better in the sight of Allaah than the scent of musk (reported by al-Bukhaari, 2/29 and Muslim, 2/806) as evidence, this mouth odour will not be dispelled by use of siwaak because it is caused by the stomach being empty, and it could occur early in the day if a person has not eaten suhoor. All the scholars are agreed that it is permissible for a fasting person to use siwaak early in the day. This shows that use of siwaak is encouraged even when fasting, and there is no difference between using it early in the day or later on.
What should be used for siwaak (cleaning the mouth)
The scholars are agreed that the best thing for cleaning the mouth is the twigs of the araak tree, because of its good smell, and because it has brush-like fibres which are effective for cleaning food particles etc. from between the teeth, and because of the hadeeth of Abd-Allaah ibn Masood (may Allaah be pleased with him) who said: I used to gather siwaak sticks from the araak tree for the Messenger of Allaah (peace and blessings of Allaah be upon him).(Reported by Ahmad, 3991; its isnaad is hasan, see al-Irwa 1/104).
If araak twigs are not available, the scholars recommended using palm-leaf stalks, or twigs of the olive tree. The ahaadeeth that have been narrated concerning this, however, are not saheeh.
The correct view is that any kind of sticks that are cleansing and not harmful may be used instead of siwaak, if it is not available, to clean the mouth and remove dirt from the teeth. This includes modern toothbrushes which are known to be beneficial in this regard.
Things that may not be used for siwaak
The scholars have stated that it is forbidden to use poisonous sticks, things that are not taahir (pure, clean), and anything that may cause bleeding, illness or any other harm.
Attributes of siwaak
The fuqaha have described the siwaak as a stick of medium length and thickness, no thicker than ones little finger, and free of knots. It should not be so wet that it will twist, because then it will not remove dirt, nor should it be so dry that it will hurt the mouth or crack during use. No doubt this is describing the ideal, otherwise the reports do not specify any particular type of siwaak. It is permissible to use any kind of siwaak that will do the job.
How to clean the mouth with siwaak
The scholars have differed as to whether siwaak should be done with the right hand or the left hand. One group the majority think that it is better to use the right hand, because of the general meaning of the hadeeth narrated by Aaishah (may Allaah be pleased with her), who said: The Messenger of Allaah (peace and blessings of Allaah be upon him) liked to start with the right when putting on his shoes, dismounting (from his camel), when cleaning himself, and in all things. (Agreed upon). (They also say that) siwaak is an act of worship and drawing closer to Allaah, so it should not be done with the left hand.
Other scholars say that it is better to use the left hand for siwaak, because it comes under the heading of removing dirt. This is the well-known opinion of Imaam Ahmads madhhab, and it is the view favoured by Shaykh al-Islam Ibn Taymiyah, may Allaah have mercy on him.
Some scholars have said that when a person is using siwaak with the intention of following the sunnah, he should use his right hand, and if he is doing it to remove dirt, he should use his left hand. The fact of the matter is that this issue is open, as there is no definitive daleel or report, and every opinion has a valid point.
The fuqaha suggested that when using siwaak, a person should start on the right, and use a side-to-side motion rather than up-and-down, as the latter may harm the gums. Among the etiquette of using siwaak, they mentioned the following:
That a person should not use the siwaak in front of others or in public, because this is impolite.
That the siwaak should be washed after use, to get rid of any dirt that may be on it. Aaishah (may Allaah be pleased with her) said: The Prophet (peace and blessings of Allaah be upon him) used to use siwaak, then he would give it to me to wash it. I would use it first, then wash it and give it back to him. (Reported by Abu Dawood, 1/45).
The siwaak should be kept in a clean place.
Using ones fingers to clean one's mouth
The scholars differ as to whether it is acceptable to use ones fingers to clean ones mouth when there is nothing else available. The correct view is that using the fingers cannot be considered as a substitute for the sunnah action, because there is no basis in Islam for doing so, and this method does not clean the mouth as a siwaak or similar instrument does. Modern methods of cleaning the teeth, like toothbrushes and so on, that remove dirt and make the mouth smell good, are acceptable.
There is nothing wrong with using siwaak that is flavoured with mint, lemon and so on, so long as they do not cause any harm. But a person who is fasting should avoid using any flavoured siwaak, and should only use natural siwaak when he is fasting.
And Allaah knows best.
Lisaan al-Arab (definition of sawaka); al-Majmoo lil-Nawawi, 1/269; Nihaayat al-Muhtaaj lil-Ramli, 1/162; Haashiyat Ibn Aabineen, 1/78; Nayl al-Awtaar lil-Shawkaani, 1/24; al-Mughni li Ibn Qudaamah, 1/78; al-Futoohaat al-Rabaaniyah ala adhkaar al-Nawawi li Ibn Allaan, 3/256; al-Sharh al-Mumti lil-Shaykh Ibn Uthaymeen, 1/137)