Is It Prohibited in Islam to Swallow Your Own Blood?
Question

Are you allowed to swallow your blood? I have read some Fatwas that during Ramadan you are not allowed to swallow your blood, but outside of Ramadan, for example if you get a paper cut or something, or a ripped lip.
Praise be to Allah.It is not permissible for the Muslim to swallow blood , whether it is a little or a lot, in Ramadan or at other times, because blood is prohibited, unless it is swallowed by mistake or involuntarily , in which case there is nothing wrong with it. Allah, may He be Exalted, says (interpretation of the meaning):
“He has forbidden you only the dead animals, and blood, and the flesh of swine, and that which is slaughtered as a sacrifice for others than Allah (or has been slaughtered for idols, on which Allah’s Name has not been mentioned while slaughtering). But if one is forced by necessity without willful disobedience nor transgressing due limits, then there is no sin on him. Truly, Allah is Oft-Forgiving, Most Merciful.” [Al-Baqarah 2:173]. 
The scholars of the Standing Committee for Issuing Fatwas were asked: 
Sometimes an individual may get a cut and he licks the blood that is coming out, which results in his swallowing the blood, or his gums bleed, so he swallows the blood that comes out. Is there anything wrong with that? 
They replied: 
“It is not permissible to swallow blood deliberately, because it is prohibited. Allah, may He be Exalted, says (interpretation of the meaning):
“Forbidden to you (for food) are: the dead animals (cattle — beast not slaughtered), blood…” [Al-Ma’idah 5:3]
With regard to swallowing it unintentionally , there is no blame in that case.”  (Fatawa Al-Lajnah Ad-Da’imah, 22/272) 
And Allah knows best.