Hazrat Alqamah says that if a person vomits deliberately while fasting, making up the fast (qada) becomes obligatory on him, and if he vomits unintentionally, making up the fast is not obligatory.

Hazrat Ali (may Allah be pleased with him) says that if a person deliberately vomits while fasting, making up (qada) that fast becomes obligatory upon him, and if vomiting occurs involuntarily, then making up (qada) is not obligatory.

It is also narrated similarly from Hazrat Mujahid.

Hazrat Abu Shaiba Mehri says that once someone asked Hazrat Thawban to narrate a hadith of the Messenger of Allah, peace and blessings be upon him. He said, I saw the Messenger of Allah, peace and blessings be upon him, break his fast after vomiting.

Hazrat Ma’dan says that Hazrat Abu Darda narrated that the Messenger of Allah (peace and blessings be upon him) broke his fast when he vomited. Ma’dan says that after this I met Hazrat Thawban and he told me that he had given water for ablution to the Messenger of Allah (peace and blessings be upon him).

Hazrat Ikrimah says that the fast is broken by something entering (the body), not by something coming out.

Hazrat Aamir was asked about the vomiting of a fasting person, so he replied that if he vomits unintentionally, he does not have to make up the fast, but if he vomits deliberately, his fast is broken.