Yet another installment in humans being fuckin weird compared to aliens: humans give blood, organs, and tissue to each other, because our race is built around being able to function under as much stress as possible.
So of course, what do we do when another human will die without something we could live without?
We go to our local hospital and undergo trauma to provide them with it, for no compensation.
Sure you might need to eat and drink more, take antibiotics or anti rejection drugs, but hey!
B'ril over there had to wait until HIS race figured out stem cells and lab grown organs, because ALL their organs are vital, and losing a pint of fluid flat out kills them or sends them into shock.