Ibn Jurayj narrated from his father that the Messenger of Allah (peace and blessings be upon him) said: "When anyone vomits, regurgitates fluid or finds prostatic fluid (madhi) while he is in prayer, let him turn away, perform ablution, then come back and build on his earlier prayer, as long as he has not spoken."
(b) Muhammad bin Yahya said: It is correct that this is mursal from Ibn Jurayj.
(c) The hadith of Ibn Jurayj through Ibn Abi Mulaykah from Aishah (may Allah be pleased with her), which Isma'il bin Ayyash narrates, is not established.
(d) Imam al-Shafi'i (may Allah have mercy on him) said: What Ibn Jurayj narrates from his father is also not established from the Prophet (peace and blessings be upon him), and what he narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) and others has been interpreted by some as washing some of the limbs.
(e) The Shaykh said: Isma'il bin Ayyash narrates it as mursal, a group narrates it from Ibn Jurayj in its preserved form, and it is indeed mursal.
(f) Imam al-Shafi'i (may Allah have mercy on him) said: Concerning what is reported from Ibn Umar (may Allah be pleased with them both) and Ibn al-Musayyab (may Allah have mercy on him), that they would have a nosebleed, then perform ablution and build on what they had already prayed: we have narrated from Ibn Umar (may Allah be pleased with them both) and Ibn al-Musayyab (may Allah have mercy on him) that they did not hold that blood requires ablution, so in our view the meaning of their ablution is washing off the blood and whatever part of the body it reached, not the ablution for prayer.
(g) It is narrated from Sayyiduna Ibn Mas'ud (may Allah be pleased with him) that after eating he washed both hands, then passed the wetness of his hands over his face and said: "This is the ablution of one who has not lost his ablution." It is well known in the speech of the Arabs that they called washing some of the limbs wudu as well, not only the complete ablution for prayer. In our view, this is the meaning of what is narrated by Ibn Jurayj, from his father, from the Prophet (peace and blessings be upon him) about performing ablution because of a nosebleed. And Allah knows best.
Imam al-Shafi'i (may Allah have mercy on him) said: This narration is not established from the Prophet (peace and blessings be upon him). The Shaykh said: What is narrated from Sayyiduna Thawban (may Allah be pleased with him) from the Prophet (peace and blessings be upon him) about vomiting is to be understood in the same way, if that narration is sound.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 670