It is narrated from Hazrat Abu Darda (may Allah be pleased with him) that once the Prophet Muhammad (peace and blessings be upon him) vomited, due to which the Prophet (peace and blessings be upon him) broke his fast. The narrator says that once I met Hazrat Thawban (may Allah be pleased with him) in the Prophet's Mosque, so I asked him about this as well. He said: I was pouring water for the Prophet (peace and blessings be upon him) for ablution.