Sayyiduna Ali (may Allah be pleased with him) said: Whoever eats out of forgetfulness while fasting, then it is provision that Allah has given him; and when he makes himself vomit while fasting, he must make it up; and when vomiting overcomes him, then there is no making up due.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8029