One of the Companions of the Prophet (peace and blessings be upon him) (may Allah be pleased with him) narrates from the Prophet (peace and blessings be upon him) that he said: "The one who vomits has not broken his fast, nor the one who has been cupped, nor the one who has had a wet dream."
(The correct version is the narration of Sufyan al-Thawri and others. A narration like that of Abd al-Rahman bin Zayd has been reported from al-Thawri, but it is not sahih (authentic). The concession in this matter has been narrated to us from Sa'd bin Abi Waqqas, Abdullah bin Mas'ud, Abdullah bin Abbas, Abdullah bin Umar, al-Husayn bin Ali, Zayd bin Arqam, Aishah bint al-Siddiq and Umm Salamah (may Allah be pleased with them all).)
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8274