Sayyiduna Abdullah al-Sunabihi (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "Whoever begins the morning fasting and then has a wet dream, or has himself cupped, or is overcome by vomiting, no make-up (qada') is due from him; and whoever makes himself vomit, make-up is due from him."
Al-Tabarani recorded it in al-Mu'jam al-Awsat. Its chain contains a narrator, Abu Bilal al-Ash'ari, and he is da'if (weak).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الصيام / 5006