Sayyiduna Fadalah bin Ubayd (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) began the morning fasting, then he (peace and blessings be upon him) vomited and broke his fast. He (peace and blessings be upon him) was asked about that, and he (peace and blessings be upon him) said: "I made myself vomit."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8032