Regarding donations of organs after death: see
https://asknoah.org/faq/organ-donations
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QUESTION: What does the Torah teach about organ donation? Is there are any difference between Jews and Noahides? I was asked to sign an organ donation card, and I don't know if I should do that.
ANSWER: Since Noahides do not have a commandment that they must be buried in the earth, the option is open to them for organ donation. Given that they have this option, it is in fact a meritorious thing for them to give this great gift of improved physical life, and even life itself, to another person. However, note that the Torah defines life by the beating of the heart. Therefore a person who wants to be an organ donor should make a clear and legal stipulation (a Torah-acceptable Living Will) that none of his organs (especially the heart!) may be removed before the heart has permanently stopped.
[For Jews, on the other, it is commanded in Deuteronomy 21:23 (which applies to all Jews) that their entire body should be buried in the earth, on the day of death or as soon afterwards as possible. The burial can be delayed beyond the first day only for certain specific circumstances.]
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While living, it is allowed to give donations from one's self for the sake of saving the lives of others, if it will not put the donor at risk of health problems. For example, a healthy person is permitted to donate blood, bone marrow, a kidney, or a part of the liver.