Some 800,000 people suffer a stroke each year in the United States and many suffer severe loss of function. According to a clinical trial led by Stanford University School of Medicine investigators, chronic stroke patients who received modified, human, adult, mesenchymal stem cells directly into their brains noticed restored motor functions. The 18 participants, all of whom had suffered their first and only stroke between six months and three years before their injections, remained conscious under light anesthesia during the procedure which involved drilling a small hole through their skulls. While more than three-quarters of these participants suffered headaches after the procedure, there were no side effects from the stem cells themselves and no known life-threatening adverse effects linked to the procedure used to administer these stem cells. In regards to improved motor functions, substantial improvements were noted in participants’ scores on metrics of stroke recovery. Due to the positive results from the trial, an expanded trial is now underway.