Musannaf Ibn Abi Shayba 3:3527

Waki' narrated to us, he said: Ali bin Salih and Isra'il narrated to us, from Ishaq, from Asim bin Damrah, from Ali, who said: "If one of you experiences in his stomach a movement (nausea), or vomiting, or a nosebleed, then let him depart and perform ablution, then let him continue his prayer, as long as he has not spoken."