The Messenger of Allah ﷺ said, "Whoever is overcome by vomiting while fasting need not make up the fast, but whoever vomits intentionally must make it up."
حدثنا مسدد حدثنا عيسى بن يونس حدثنا هشام بن حسان عن محمد بن سيرين
قال رسول الله ﷺ من ذرعه قيء وهو صائم فليس عليه قضاء وإن استقاء فليقض
[Its isnad is daif] Tirmidhi transmitted it, Fasting, chapter on what has been said about one who deliberately induces vomiting, hadith 720, and Ibn Majah, hadith 1676, from the hadith of Isa bin Yunus through this route. Ibn Khuzayma graded it sahih, hadith 1960, 1961, as did Ibn Hibban, hadith 907, and Hakim, 1/426, 427, saying it meets the standard of the two Shaykhs, and Dhahabi agreed with him.Hisham bin Hassan is a mudallis and he narrated using anaana. This hadith has other daif routes. Bayhaqi transmitted, 4/219, and Ibn Abu Shayba, 3/38, hadith 9188, with sahih chains of transmission, from Ibn Umar, who said, "Whoever is overcome by vomiting owes no makeup fast, but whoever deliberately induces vomiting must make it up."