Abu Shaybah al-Mahri (may Allah have mercy on him) said: We said to Thawban (may Allah be pleased with him): Narrate a hadith to us from the Messenger of Allah (peace and blessings be upon him). He said: I saw the Messenger of Allah (peace and blessings be upon him) vomit, and then he (peace and blessings be upon him) broke his fast.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8031