Liaison office of Grand Ayatullah Sayyid Ali Al Sistani (L.M.H.L) in London, Europe, North and South America.
Niyyat for fasting
It is not necessary for a person to pass the niyyat for fasting through his mind or to say that he would be fasting on the following day. In fact, it is sufficient for him to decide that in obedience to the command of Allah he will not perform from the time of Adhan for Fajr prayers up to Maghrib, any act which may invalidate the fast.
And in order to ensure that he has been fasting throughout this time he should begin abstaining earlier than the Adhan for Fajr prayers, and continue to refrain for some time after sunset from acts which invalidate a fast.
Things which make a Fast void
There are nine acts which invalidate fast:
1- Eating and drinking
2- Sexual intercourse
3- Masturbation (Istimna) which means self abuse, resulting in ejaculation
4- Ascribing false things to Almighty Allah, or his Prophet or to the successors of the Holy Prophet
5- Swallowing thick dust
5- Immersing one's complete head in water
7- Remaining in Janabat or Haidh or Nifas till the Adhan for Fajr prayers
8- Enema with liquids
Note: If a fasting person intentionally immerses his entire head in the water, his fast is known to be void, even if the rest of his body remains out of water. But this act does not invalidate the fast; it is a Makrooh act, and as a measure of precaution, should be avoided.
Note: Swallowing saliva does not invalidate a fast, although it may have collected in one's mouth owing to thoughts about sour things etc.
Note: There is no harm in swallowing one's phlegm or mucous from head and chest as long as it does not come upto one's mouth. However, if it reaches one's mouth, the obligatory precaution is that one should not swallow it.
Things which are Makrooh for a person observing Fast
Certain things are Makrooh for a person observing fast, some of them are mentioned below:
1- Using eyedrops and applying Surma if its taste or smell reaches the throat.
2- Performing an act, which causes weakness, like blood-letting (extracting the blood from the body) or going for hot bath.
3- Inhaling a snuff if one is not aware that it might reach the throat; and if one is aware that it will reach the throat its use is not permissible.
4- Smelling fragrant herbs.
5- For women, to sit in the water.
6- Using suppository, that is, letting into rectum a stimulant for bowels.
7- Wetting the dress which one is wearing.
8- Getting a tooth extracted or doing something as a result of which there is bleeding in the mouth.
9- Cleaning the teeth with a wet toothbrush.
10- Putting water or any other liquid in the mouth without a good cause.
It is also Makrooh for a fasting person to court or woo his wife without the intention of ejaculation; or to do something which excites him sexually. And if he does it with the intention of ejaculation, and no ejaculation takes place, his fast, as an obligatory precaution, will be deemed void.