The kidneys are two bean-shaped organs found on the left and right sides of the body. They filter the blood in order to make urine, to release and retain water, and to remove waste and nitrogen (the excretory system). Each kidney accounts for 50% of a person's blood filtration. It is possible to survive with only one. Carcinoma, one form of tumor cancer, weakens blood filtration.
Human kidneys can be surgically removed to be donated or sold for transplantation. Removing a kidney from a guest or prisoner decreases faction goodwill by 20 points down to a max of -100. Surgery of your own people, gives the original body a -30 mood penalty and -5 mood to other members.