The Sunan collections also contain two hadiths:

One is the hadith transmitted by Hishām ibn Hassān, from Muhammad ibn Sīrīn, from Abū Hurayrah—may Allah be pleased with him—who reported that the Messenger of Allah—may Allah bless him and grant him peace—said:

“Whoever is overcome by vomiting while fasting need not make up the fast. But if he induces vomiting, he must make it up.”

Some scholars did not consider this hadith established; rather, they held it to be a statement of Abū Hurayrah. Abū Dāwūd said: “I heard Ahmad ibn Hanbal say, ‘There is nothing sound in this.’”

Al-Khattābī said: “He means that the hadith has not been reliably preserved.” Al-Tirmidhī said: “I asked Muhammad ibn Ismā‘īl al-Bukhārī about it, but he knew it only through ‘Īsā ibn Yūnus. He said, ‘I do not consider it reliably preserved.’”

He said: “Yahyā ibn Kathīr narrated from ‘Umar ibn al-Hakam that Abū Hurayrah did not regard vomiting as invalidating the fast.”

Al-Khattābī said: “Abū Dāwūd mentioned that Hafs ibn Ghiyāth narrated it from Hishām just as ‘Īsā ibn Yūnus did.”

He said: “I know of no disagreement among the scholars that someone overcome by vomiting need not make up the fast, or that someone who deliberately induces vomiting must make it up. They differed, however, over expiation. The majority of scholars said that he need only make up the fast. ‘Atā’ said that he must both make it up and offer expiation. This was also reported from al-Awzā‘ī, and it is the view of Abū Thawr.”