It is pertinent to mention that fasting can become void if a fast-observer engaged in some acts within the stipulated hours of fasting. Those acts are referred to as fast invalidators. According to the religious verdicts (Fatawa) of religious authorities, acts that invalidate fast are:
1. Eating and drinking: If a fast-observer eats or drinks on purpose and knowingly, his fast is void. It makes no difference whether it is among normal food and drink, or non-edible like a piece of cloth or paper, whether it is a lot or a little like a very tiny drop of water or a small crumb of bread. However, if a fasting person eats or drinks something inadvertently (sahwan), his fast does not become invalid.
In addition, if a fast-observer deliberately swallows something that comes out of his mouth and after getting to the oral cavity, the fast is void. However, doing so inadvertently does not invalidate the fast. Swallowing the mucus (from the head/lung) does not make one liable for anything. However, after the mucus enters the mouth, one should — by obligatory caution — avoid swallowing it. Meanwhile, swallowing saliva does not invalidate a fast even though it may have collected in one’s mouth as a result of thinking about food and suchlike.
2. Sexual intercourse: Sexual intercourse invalidates a fast even if penetration is as little as the circumcised part of the penis, and even if there is no ejaculation. It is not permissible for a person to have sex with his wife (during the day) of the month, even if the man cannot fast. A man having foreplay with his wife during the day in the month of Ramadan does not affect his fast, as long as it does not result in ejaculation. If someone forgets that he is fasting and has sex, his fast is in order. However, as soon as he remembers, he should terminate it; otherwise, his fast is not valid. If during the month of Ramadan, a man had sexual intercourse with his wife with her consent. The rule of intentional breaking of the fast applies to both of them. Hence it is obligatory for both of them to perform its Qaḍā’ along with kaffārah.
3. Masturbation (Istimna): Masturbation is when a man – either with himself or by means of something – does something other than having sexual intercourse that results in ejaculation. If a fasting person masturbates, his fast becomes invalid. However, if a person ejaculates involuntarily, his fast does not become invalid. If a fasting person masturbates deliberately and semen is discharged, total kaffarah is not obligatory on them. However, a mustahab caution is that they pay a total atonement (kaffarah jam’).
4. Ascribing false things to Almighty Allah, or His Prophet or to his successors (12 Imams): If a fasting person intentionally ascribes something false to Allah, Prophet Muḥammad (PBUHH), or the Twelve Imams (PBUT) – whether he does this verbally, in writing, or by making a sign and suchlike – and even if he immediately says ‘I have lied’ or he repents, then based on obligatory precaution his fast is invalid. The same applies, based on recommended precaution, to ascribing something false to Her Eminence [Fatimah] al-Zahra (PBUH) and to the other Prophets and their successors. There is no difference between whether he repents later and declares that it was a lie.
Meanwhile, if someone wishes to report a narration about which he does not have any evidence as to its authenticity, and he does not know whether it is true or false, then based on obligatory precaution he must report it in such a way that he does not directly attribute it to Prophet Muḥammad or the Imams.
5. Swallowing thick dust: Based on obligatory precaution, causing thick dust to reach one’s throat invalidates a fast, whether the dust is of something that is lawful (ḥalāl) to eat, such as flour, or it is of something that is unlawful (ḥarām) to eat, such as soil. Causing dust that is not thick to reach the throat does not invalidate a fast. Swallowing the smoke of cigarettes and other tobacco products invalidates fast by obligatory caution. Therefore, one must guard against it. However, the entering of dust into the mouth and the nose does not invalidate the fast unless it reaches the throat. By obligatory caution, a fasting person should avoid all tobacco products as well as drugs absorbed through the nose or (under the) tongue.
6. Immersing one’s head in water: Immersing one’s head completely into water invalidates fast by obligatory caution and one should perform its qaḍā’ later. And it makes no difference whether or not one’s body is inside the water while he puts the whole head under water. If one immerses one half of his head into the water and takes it out to put the other half under the water, the fast is valid. But if one doubts whether or not the whole head is under the water, the fast is valid. Also, one’s fast is not affected by pouring water over one’s head with a jug or the like.
If a fasting person falls into water unintentionally so that the whole head is under the water, the fast is not void but he should bring his head out of the water right away. Also, if he forgets that he is fasting and immerses his head under the water, the fast is valid. However, he should take it out as soon as he remembers.
NOTE: According to the religious verdict of Ayatollah Sistani, immersing the entire head in water does not invalidate the fast but it is highly disapproved (makrūh).
7. Remaining in the state of Janabat or Haidth or Nifas till the Adhan of Fajr: During the month of Ramadan, if someone becomes junub or if a woman finishes her menstruation or childbirth bleeding, he/she should make a ritual bath (i.e., ghusl) before the morning adhān. If he does not make ghusl before adhān, his fast is not valid.
In the month of Ramadan, one whose duty is to make ghusl before morning adhān but is unable to do so, e.g., as the time is too short or water is harmful to him, he should make tayammum instead of ghusl. If in the month of Ramadan, a junub intentionally does not perform ghusl until the time of Ṣubḥ prayers – or, if his duty is to perform dry ablution (tayammum) and he does not perform it – he must complete the fast of that day with the intention of mā fī al-dhimma and he must also fast another day [after Ramadan]. And with regard to the fast on this additional day, as it is not known whether it is a fast of qaḍāʾ or punishment, he must keep it with the intention of mā fī al-dhimma, not with the intention of qaḍāʾ.
If on a night of the month of Ramadan, someone knows that he will not have time to perform ghusl or tayammum and yet intentionally becomes junub, his fast is invalid and qaḍāʾ and kaffārah become obligatory on him [i.e., he must keep a fast after Ramadan and also give recompense]. If a woman’s ḥayḍ or nifās stops on a night of the month of Ramadan before the time of ṣubḥ prayers and she intentionally does not perform ghusl, or, if her duty is to perform tayammum and she does not do so, she must complete the fast of that day and also keep a qaḍāʾ fast for that day. Furthermore, with regard to a qaḍāʾ fast of the month of Ramadan, if she intentionally does not perform ghusl or tayammum before the time of ṣubḥ prayers, then based on obligatory precaution she cannot fast on that day.
If a woman’s ḥayḍ or nifās stops near the time of ṣubḥ prayers in the month of Ramadan but she does not have time to perform ghusl or tayammum, her fast is valid. If a woman’s ḥayḍ or nifās stops after the time of ṣubḥ prayers, she cannot fast on that day. Furthermore, if she experiences ḥayḍ or nifās during the day while she is fasting, then even if it is near the time of maghrib prayers, her fast is invalid.
8. Enema with liquids: If a liquid enema is taken by a fasting person, his fast becomes void even if is obliged to take it for the sake of treatment. In other words, applying a liquid enema – even if one is obliged to or for the purposes of treatment – invalidates a fast.
9. Vomiting: Whenever a fasting person intentionally vomits, his fast becomes invalid even if he vomited out of necessity or because of illness or suchlike. However, if he vomits unintentionally or involuntarily, there is no problem [and his fast remains valid]. If a person unintentionally swallows something and remembers that he is fasting before it reaches his stomach, and if it goes down to such an extent that were he to then make it enter his stomach it could not be called ‘eating’, it is not necessary for him to bring it out and his fast is valid. If someone burps and something comes up in his throat or mouth, he must spit it out; and if he swallows it involuntarily, his fast is valid.
