Liver failure is the 12th leading cause of adult deaths in developed nations. Currently, the only cure for end-stage liver failure is to transplant a new human liver, which are in short supply. Our CIRM-supported project has succeeded in mass producing large numbers of human liver cells in a Petri dish from pluripotent cells. We are rigorously testing whether injection of these human liver cells into mice with liver failure can improve their survival. Our long-term goal is to mass produce new human liver cells to provide an abundant source of cells to transplant into patients with liver failure.