Abstract: The invention relates to agents for the treatment of viral infections, in particular, infections with hepatitis and retro-viruses. Said agents inhibit the release, maturation and replication of both retro-viruses and also hepatitis viruses. In the example of human immune deficiency virus (HIV) and hepatitis-B viruses it has been shown that proteasome inhibitors block the release of virus particles and the infectiousness of the released viral particles and thus the reproduction of the viruses. The proteasome inhibitors affect the activities in the ubiquitin/proteasome pathway, in particular the enzymatic activities of the 26S and the 20S proteasome complexes. The application for the above invention lies in anti-retroviral therapy, particularly the treatment of HIV infections and AIDS and in the anti-viral therapy of hepatitis infections, in particular the treatment of acute and chronic HBV and HCV infections and the associated liver carcinomas.