Researchers across the globe are working with pigs as sources of cell, tissues and organs for xenotransplantation. Studies include the use of pancreatic islet cells and neural cells from pigs for insulin-dependent diabetes and refractory parkinsonism, as well as perfusion of a patient’s fluids through a pig liver situated outside the patient’s body as a temporary strategy to treat liver failure. Patients with Huntington’s disease, which is a neurodegenerative condition characterized by uncontrolled movement and mental deterioration, also are receiving modified tissues (skin and nerves) from pigs as an experimental treatment. Most recently successful organ transplants of the heart and kidney have been performed using genetically engineered pig organs. Collectively, these studies are testing the safety and effectiveness of this promising source.