The Prophet ﷺ said: if one has a sudden attack of vomiting while one is fasting, no atonement is required of him, but if he vomits intentionally he must make atonement.

قَالَ رَسُولُ اللَّهِ ﷺ مَنْ ذَرَعَهُ قَىْءٌ وَهُوَ صَائِمٌ فَلَيْسَ عَلَيْهِ قَضَاءٌ وَإِنِ اسْتَقَاءَ فَلْيَقْضِ

“Whoever unintentionally vomits, he does not have to make up for the fast, but whoever makes himself vomit, has to make up for the fast.”

عَنِ النَّبِيِّ ﷺ قَالَ مَنْ ذَرَعَهُ الْقَىْءُ فَلاَ قَضَاءَ عَلَيْهِ وَمَنِ اسْتَقَاءَ فَعَلَيْهِ الْقَضَاءُ

Yahya related to me from Malik from Nafi that Abdullah ibn Umar used to say, "If some one makes himself vomit while he is fasting he has to make up a day, but if he cannot help vomiting he does not have to make up anything."

أَنَّهُ كَانَ يَقُولُ مَنِ اسْتَقَاءَ وَهُوَ صَائِمٌ فَعَلَيْهِ الْقَضَاءُ وَمَنْ ذَرَعَهُ الْقَىْءُ فَلَيْسَ عَلَيْهِ الْقَضَاءُ

[Machine] The Messenger of Allah ﷺ said, "Whoever is able to endure should fulfil it (the command of Allah) and whoever is weak in enduring, they should fulfill it whatever they are able to bear."

قَالَ رَسُولُ اللهِ ﷺ مَنْ ذَرَعَهُ الْقَيْءُفَلَيْسَ عَلَيْهِ قَضَاءٌ وَمَنْ اسْتَقَاءَ فَلْيَقْضِ

[Machine] The Messenger of Allah ﷺ said, "Whoever is overwhelmed by vomiting, it is not obligatory for him to make up for missed prayers. And whoever intentionally vomits, he must make up for the missed prayers." This is an authentic hadith according to the condition of the two sheikhs (referring to Abu Bakr and Umar) and they did not exclude it.

قَالَ رَسُولُ اللَّهِ ﷺ «مَنْ ذَرَعَهُ الْقَيْءُ فَلَيْسَ عَلَيْهِ قَضَاءٌ وَمَنِ اسْتَقَاءَ فَلْيَقْضِ» صَحِيحٌ عَلَى شَرْطِ الشَّيْخَيْنِ وَلَمْ يُخَرِّجَاهُ

[Machine] The Messenger of Allah ﷺ said: "Whoever vomits involuntarily while fasting, there is no need for them to make up for the fast. But whoever deliberately induces vomiting, they must make up for the fast."

قَالَ رَسُولُ اللَّهِ ﷺ «مَنْ ذَرَعَهُ الْقَيْءُ وَهُوَ صَائِمٌ فَلَيْسَ عَلَيْهِ قَضَاءٌ وَمَنِ اسْتَقَاءَ فَلْيَقْضِ»