With clinicians from the Princess Alexandra Hospital we are currently undertaking a small clinical trial of cell transplantation therapy by removing cells from the paraplegics and transplanting them into their own injured spinal cord. The transplanted cells are not "stem cells" but "olfactory ensheathing cells", cells that promote regeneration of the olfactory sensory neurons and guide the growth of their connections from the nose to the brain. The promise of “stem cells” is that they have the potential to repair or replace any part of the body damaged or lost by injury or disease. "Embryonic stem cells" are isolated from human embryos and are capable of making all the cells in the body. "Adult stem cells" are isolated from adult tissues and give rise to multiple cell types and are commonly thought to be involved in tissue repair. The most widely studied adult stem cells are the haematopoietic stem cells, the cells in the bone marrow that give rise to blood cells. Adult stem cells also exist in several brain regions and there is great interest in developing ways to stimulate these brain stem cells to repair the brain, for example after stroke or Parkinson’s disease. The olfactory sensory neurons in the nose are continually replaced throughout life from a stem cell that we have shown recently can develop into many different cell types, apart from olfactory sensory neurons. This source of adult stem cells holds potential for cell therapies in which a patient’s own cells are transplanted back into their own body, obviating the technical and ethical issues of embryonic stem cells and the problems of transplant rejection by the immune system. This talk will discuss the biology of olfactory stem cells and propose how they might be used for cell transplantation therapies in the future.