In addition to cardiac death, brain death has also been considered the end of life since 1968. However, scientists are increasingly expressing doubts. Transplantation medicine needs a death criterion, because vital organs can only be removed from the dead. But are organ donors really dead? Since the first successful heart transplant in 1967, organ donation has been part of everyday clinical practice in many countries. However, acceptance seems to be declining in some countries: In Germany, the number of post-mortem organ donors is falling continuously, from 1,200 people in 2011 to 797 in 2017. And in countries such as Japan, transplant medicine has been viewed critically by the population for decades and is hardly ever used.