A bone marrow transplant is a procedure that can be life-saving - for example, for people with leukaemia or lymphoma. Preparation for the procedure is quite complicated. What the transplant itself looks like, however, is quite astonishing to many people. What you need to know about bone marrow transplantation: in which situations does it take place, from whom can the transplanted cells originate and what are the risks associated with bone marrow transplantation?