What is the ruling on food repeatedly and involuntarily returning to the throat during Ramadan?

The unintentional return of some food to the throat does not invalidate the fast, whether the fasting person did not swallow it or swallowed it unintentionally. However, if he swallows it intentionally when he could have expelled it, his fast is invalidated. It is stated in "Futuhāt al-Wahhāb": "If he wakes up and experiences the aforementioned belch, he should spit it out and wash his mouth, and his fast is not broken, even if this happens repeatedly." Sheikh Ibn 'Uthaymeen said: If some food comes out with a belch and reaches the mouth, it is not permissible to swallow it intentionally. Whoever swallows it knowingly has broken their fast; rather, they must spit it out. But if he swallowed it while unaware that it was forbidden for him, his fast is valid.