Wudu is not invalidated by bleeding from the body
Question

Is Wudu invalidated by bleeding from the body?.
Praise be to Allah.If impure substances come out of the body, one of the following three scenarios must apply: 
-1- 
It is urine or stools and comes out from the usual exit. This invalidates Wudu, according to evidence from the Quran and Sunnah, and scholarly consensus. 
Allah says (interpretation of the meaning): 
“But if you are ill or on a journey, or any of you comes after answering the call of nature, or you have been in contact with women (i.e. sexual intercourse), and you find no water, then perform Tayammum with clean earth and rub therewith your faces and hands” [Al-Maa’idah 5:6]
Al-Tirmidhi (96) narrated that Safwaan ibn ‘Assaal (may Allah be pleased with him) said: The Messenger of Allah (peace and blessings of Allah be upon him) used to command us, if we were travelling, not to take off our khufoof (leather slippers, socks and the like) for three days and three nights except in the case of janaabah, but not stools, urine or sleep. Classed as saheeh by al-Albani in Saheeh al-Tirmidhi. 
Stools, urine or sleep are things that invalidate Wudu.  
-2- 
If urine or stools come out from a place other than the usual exit, such as one who has had surgery and they now come out from an opening in his stomach, for example. This invalidates Wudu because the evidence quoted above indicates that Wudu is invalidated when urine and stools come out, and the general meaning indicates that this applies whether they come out of the usual exit or elsewhere. 
-3- 
The impurity that is coming out of the body is not urine or stools, such as blood and vomit, according to those scholars who say that vomit is impure. 
This is a matter concerning which the scholars differed. Some of them – such as Imam Abu Haneefah and Ahmad – were of the view that they do invalidate Wudu, although they differed concerning the details.  
They quoted a number of texts as evidence for that: 
1 – The words of the Prophet (peace and blessings of Allah be upon him) to the woman who was suffering from istihaadah (non-menstrual vaginal bleeding): “That is from a vein, so do Wudu for every prayer.” They said: The reason why Wudu is required may be that it is bleeding from a vein, and this applies to every kind of bleeding. 
2 – The report narrated by al-Tirmidhi (87) from Ma’daan ibn Abi Talhah from Abu’l-Darda’ (may Allah be pleased with him), that the Messenger of Allah (peace and blessings of Allah be upon him) vomited and broke his fast, then he did Wudu. I met Thawbaan in the mosque of Damascus and mentioned that to him. He said: That is right; I poured the water for his Wudu. Classed as saheeh by al-Albani in Saheeh al-Tirmidhi. 
Many scholars are of the view that the emission of impurities from the body does not invalidate Wudu, and they quoted as evidence the fact that the basic principle is that Wudu is not invalidated, and there is no saheeh evidence to indicate that Wudu is invalidated by that. 
Al-Nawawi (may Allah have mercy on him) said: 
My inclination concerning this matter is to say that the basic principle is that Wudu is not invalidated unless there is proof in sharee’ah, and there is no proof in this case. End quote. 
They responded to the evidence quoted by those who say that it does invalidate Wudu by noting the following: 
With regard to the hadith about the woman who was suffering from istihaadah, they responded that what the Prophet (peace and blessings of Allah be upon him) meant by that was to point out that it was not menstrual blood, rather it was bleeding from a vein, and as that was the case, she should not stop praying, rather she should pray, but she should do wudoo for every prayer. 
Al-Nawawi said in al-Majmoo’: If it – the hadith about the woman who was suffering from istihaadah – is saheeh, what it means is that this bleeding is not menstrual blood, rather it requires Wudu because it comes out from the same area as urine comes out. It does not mean that the emission of blood, from any site, requires Wudu. End quote. 
With regard to the hadith of Thawbaan, they noted several points in response to it: 
1 – That it is da’eef (weak). Al-Nawawi said in al-Majmoo’: As for the response to their quoting the hadith of Abu Darda’ as evidence, the response to that can be made in several ways, the best of which is that it is da’eef mudtarab (weak). This was stated by al-Bayhaqi and other scholars. End quote.
2 – Even if it is saheeh, it does not indicate that Wudu is invalidated by vomiting, because it is simply a report of something that the Messenger (peace and blessings of Allah be upon him) did. It indicates that it is mustahabb to do Wudu after vomiting, not that it is obligatory. 
See: al-Majmoo’ 2/63-65; al-Mughni, 1/233, 234 and 1/247-250; al-Sharh al-Mumti’, 1/185-189 
And Allah knows best.