Many people can be organ donors after they have died. In the vast majority of cases, this occurs in hospital after someone has had a sudden death and the organs can be removed from the body very quickly. However it is possible for patients with cancer or other longer term conditions to donate some organs such as their corneas and their heart valves. These organs can be removed from the body a short while after death, meaning you can still be a donor even if you wish to die at home or in the Hospice.
You can donate any organ or tissue you choose, including your brain, to medical science. If this is what you want to do, make sure you write it down (or make an Advance Statement) and tell your family and your GP. More information on organ donation.