I work in the health field, and part of my job entails preparing blood for transfusion. We are currently experiencing a severe blood shortage. I would like to know if it permissible for a Muslim to donate blood. It is not certain whether the blood will be given to a Muslim or non-Muslim, but living in America, the majority are Kuffar. It is noted that to prolong the life of a Kafir is not allowed since he will use “Muslim” blood to commit acts of evil and that Muslims should only donate to Muslims. Please clarify in detail your response.

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

If a person is in dire need of the blood of another person, and if transferring the blood to that person is the only way to save his/her life, then transferring the blood is permissible provided reliable specialists in this field confirm the necessity.
Allah Says (what means):

• {But whoever is forced [by necessity], neither desiring [it] nor transgressing [its limit], there is no sin upon him. Indeed, Allah is Forgiving and Merciful.} [Quran 2:173]

• {…while He has explained to you in detail what is forbidden to you, except under compulsion of necessity?} [Quran 6: 119]

Therefore, donating blood is permissible if it is confirmed that it does not cause any harm to the donor himself. Similarly, asking blood from people whether they are Muslims or not is also permissible at the time of necessity in order, for instance, to save the life of a person whether or not he is a Muslim. On the other hand, donating blood to non-Muslims is permissible if they are not among those who are in the state of war against Muslims.

The fact that a non-Muslim will remain on his disbelief after his life is saved, or after being relieved from the pain or disease he was facing, then this does not change the ruling concerning donating blood. This is because all the Muslim scholars are agreed that feeding a non-Muslim who is not in a state of war against Muslims is permissible; in some occasions it even becomes an obligation, such as when a non-Muslim's life is in danger because of starvation and a Muslim has some food that exceeds his dire necessity. In this case, he is obliged to feed him. Moreover, this is a kind of favor and kindness which a Muslim is required to do even for a non-Muslim, as Allah Says in this regard (what means): {Allah does not forbid you from those who do not fight you because of religion and do not expel you from your homes – from being righteous toward them and acting justly toward them. Indeed, Allah loves those who act justly.} [Quran 60:8]

Know that a Muslim is rewarded for every good deed that he does even if that deed is done to animals. The Prophet said: “There is a reward in every creature with a moist liver (i.e. any living creature).” [Al-Bukhari]

Perhaps this helps; i.e., helping a non-Muslim to relieve him from his pain may be a way to make him interested in Islam and to let him observe the beauty of Islam. So, he may embrace Islam, and thus, you may be a reason to save him from going to Hell.

For more benefit on blood donation, please refer to Fataawa 82197, 87533, 129802, 84292, and 83172.

Allah knows best.