The different aspects of brain death are discussed. It is pointed out that the diagnosis of poisoning as the cause of brain death can be checked by toxicological examination of brain tissue and of blood in the sinus of the dura mater, since the metabolism in the brain and sinus blood is markedly reduced while drugs and toxic substances continue to be broken down in the other organs. Particular importance attaches to this difference in the case of crimes of violence creating conditions that predispose to brain death when the significance of a further violent act, e.g. stabbing with resultant haemorrhage, has to be assessed. The simple vital reaction of bleeding does not of itself constitute proof in such a situation, unless it is possible to say with a good degree of certainty that brain death did not occur at the moment when the victim was stabbed. It may, however, be possible to state that brain death that could have been caused by violence has not yet occurred if complex vital reactions, such as inflammation of a wound, are seen.