Extensive studies of GBV-C/HGV in acute and chronic hepatitis non-A-non-E have failed to provide hard evidence for a major role in this disease. Persistent GBV-C/HGV viraemia is in most cases associated with normal ALT levels, and only in a minority of patients are mild elevations of aminotransferases found. Its disease-inducing capacity is questionable and the findings accumulated so far are best explained by looking at GBV-C/HGV as a well-adapted, predominantly parenterally transmitted, persistent virus; it might be transmitted concomitantly with another, still unidentified hepatitis non-A-non-E virus. This does not exclude the possibility that GBV-C/HGV might, in some rare cases and under certain circumstances, induce a hepatitis-like illness as seen with other viruses such as EBV or CMV, GBV-C/HGV definitely plays a minor role only, if any, in post-transfusion and community-acquired hepatitis non-A-non-E.