Q: Is a Noahide allowed to eat blood?
Q: Is a Noahide allowed to eat (or drink) blood? It seems that this is not explicitly prohibited.
A: There are only two cases where blood is forbidden to a Noahide. (1) Blood from a creature which has been removed while the creature is still alive. Examples would be blood that is collected while an animal is slaughtered or blood that is taken from the artery in a horse's neck, or a common type of sausage which includes blood taken straight from a live pig. Human blood that was collected for a blood donation would also be included in this. (2) If the Noahide has explicitly accepted the prohibition of eating blood. This is not recommended, because the laws prohibiting eating blood for Jews are very complicated. On the other hand, a Noahide can accept some or all of the prohibitions related to blood as a nonbinding custom by making an explicit declaration – for example, "I will refrain from eating blood, without taking on a definite obligation, and if I decide to change my mind it will not be a sin."