Brain injury and stroke kill huge numbers of Americans annually, and permanently disable many more. Few effective treatments. Donald Stein, the world-renowned leader of our Brain Injury Research Laboratory, was the first scientist in the world to note that progesterone, a naturally occurring hormone, protects damaged brain tissue. With funding provided by the NIH, we recently completed the world's first study of this treatment in human victims of acute traumatic brain injury. Research conducted in our lab suggests that progesterone may also confer protection in the setting of acute stroke. If our promising observations are confirmed, this research will revolutionize treatment of both conditions.