Recent work in animals by the research group at Yale University School of Medicine has shown that the combination of UDCA and ATRA produced a significant improvement in liver scarring and inflammation in animals with bile duct disease similar to that seen in PSC. This improvement included a lowering in the levels of bile acids, which are harmful to the liver, and a lowering of inflammation in the liver tissue of these animals. The benefits seen in this study were greater in animals receiving the combination of UDCA and ATRA compared to animals who received either medicine alone.