Dr. Cheung's past research utilized the duck animal model to study the mechanism of viral neutralization of hepatitis B virus at the molecular level. In collaboration with basic scientists, he is interested in using molecular biology approaches to study clinical samples from chronic hepatitis C patients and investigate the host-virus interaction. The ultimate goal is to understand the pathogenesis of HCV and mechanism of anti-viral therapy. Dr. Cheung is also investigating the healthcare model of hepatitis C care among infected veterans, interaction between hepatitic C infection and alcoholic cirrhosis, and impact of comorbid conditions on the health related quality of life. He is investigating methods to improve care of veterans with chronic hepatitis C, including use of the novel experimental anti-viral therapies as part of clinical trails. Dr. Cheung also used VA and other database to study various healthcare issues in patients with chronic hepatitis C.