Works : Islamic Laws
1655. If a fasting person vomits intentionally his fast becomes void, though he may have been obliged to do so on account of sickness. However, the fast does not become void, if one vomits forgetfully or involuntarily.
1656. If a person eats something at night knowing that it will cause vomiting during the day time, the recommended precaution is that he should give the qadha of that fast.
1657. If a fasting person can stop vomiting without causing any harm or inconvenience to himself, he should exercise restraint.
1658. If a fly enters the throat of a fasting person, it will not be necessary to throw it out if it has gone deep down the gullet, and his fast will be valid. But if it has not descended deep down, it must be coughed out, even by vomiting, if it is not harmful to do so. If one does not do so, fast will be void.
1659. If a person swallows something by mistake and remembers before it reaches the stomach that he is fasting, it is not necessary for him to throw it out, and his fast is in order.
1660. If a fasting person is certain that if he belches, something will come out from the throat, he should not, as a precaution, belch intentionally, but there is no harm in his belching if he is not certain about it.
1661. If a fasting person belches and something comes from his throat or into the mouth, he should throw it out, and if it is swallowed unintentionally, his fast is in order.