As far as the ‘Hissiyyah’ it’s a must to reiterate. And they are eating and drinking, intentionally eating and drinking. Allāh (ﷻ) says,
“And eat and drink until the white thread (light) of dawn appears to you distinct from the black thread (darkness of night).” (2:187)
So if Fajr comes, he refrains from eating and drinking because eating and drinking after Fajr comes breaks his fast and it’s a must to reiterate because some of the people might be late and are not aware of the Adhān. Then he eats and drinks after the Adhān and says, “I’m going to fast.” So he eats and drinks after Fajr comes. So there is no fasting for him he was supposed to refrain. So there is no fasting for him. It’s upon him to make it up because he intentionally ate and drank after Fajr came. As for the one who ate and drank forgetfully, then there is nothing upon him. His fasting is valid. The Prophet (ﷺ) said, “Whoever forgetfully eats and drinks while he is fasting, then let him complete his fasting, for indeed Allāh has fed him and gave him drink.”
An example of eating and drinking is what enters the body from the rest of the things like medicine tablets or liquid medicine. They break the fast because it enters his body and this is the ruling in regards to eating and drinking. Likewise nutritional infusion and all the other types of nutrition break the fast because this is what is meant by eating and drinking. Likewise dialysis, because it carries liquid. Also blood analysis enters his inside so it breaks his fast, however, he is excused for treatment. However he makes up that day because he is sick. And the one sick breaks his fast. Allāh permits the sick to break his fast. And he permits him to perform dialysis however he makes up the day.
Likewise, vomiting is from the things that break the fast. Vomiting is what is in the stomach from the way of the mouth because he caused this vomiting. So if he vomits he breaks his fast because he took out what was in his stomach from his food and drink that gave him strength, so he breaks his fast. As what’s in the ḥadīth,
“Whoever vomits then let him make it up.”
or as it comes in the ḥadīth of the Messenger of Allāh (ﷺ). As for the one who his vomit overcomes him unintentionally then he doesn’t break his fast with that. His fast is valid because he unintentionally vomited.
Likewise from the things that break the fast is sexual intercourse. “So now have sexual relations with them and seek that which Allāh has ordained for you (offspring) and eat and drink until the white thread (light) of dawn appears to you distinct from the black thread (darkness of the night). (2:187) Sexual relations break the fast, regardless if he ejaculates or doesn’t. If he enters her, then he has broken his fast; regardless if he ejaculates or not. As for if semen comes out without sexual relations like masturbation then this also breaks the fast. However, he doesn’t need expiation. He only needs to make up the day and repent to Allāh, not expiation. As for sexual intercourse during the days of Ramadhān, the he must repent to Allāh; make up the day and upon him is a heavy expiation of fasting two consecutive months. The first is freeing a slave. If he can’t find a slave to free, then he fasts two consecutive months. If he can’t fast two consecutive months, then he feeds sixty of the poor and that is the expiation of the sexual intercourse during the days of Ramadhān. And for the women is the same, if she willingly accepts then for her is the same. As for if she is forced then there is no blame upon her regarding that, her fast is not broken because she was forced. And the sin is only upon him and this affair is obligatory for the Muslim to be conscious of and to really distance himself from it. So the one that can’t control his desires or his limbs, then let him not approach his wife for fear that it will drive him to a consequence he can’t bear, so let him distance himself from her.
And from the things that break the fast is removing blood from the body whether its by cupping its by donating blood, or by helping someone sick. Indeed cupping breaks the fast, as it comes in the authentic ḥadīth that the Prophet (ﷺ) saw a man being cupped while he was fasting. He (ﷺ) said the one cupping and being cupped breaks the fast.” Drawing a lot of blood breaks the fast. As for a little amount of blood for a sample analysis to analyze a drop or two, then this doesn’t affect the fast because it’s not like cupping. Likewise if a wound of a person fasting bleeds profusely, then this doesn’t affect the fast because this is not by his choice.
So it is upon the Muslim to preserve his fast and to avoid the things that break his fast, the Hissiyah and Ma'nawiyyah so that his fast is valid, and benefits him with Allāh (ﷻ).