Reactive oxygen and nitrogen species play complex roles in the physiological regulation of cell metabolism and in many disease processes as well, including viral infections. Viral replication occurs within living cells and is totally dependent on its host's biosynthetic machinery. Many intracellular signaling pathways exploited by viruses for their own replication are regulated by the oxidoreductive (redox) state of the host cell. Consequently, factors that alter the balance between reactive oxygen/nitrogen species and antioxidant molecules/enzymes-including metabolic conditions like malnutrition, obesity, and diabetes-can influence cells' susceptibility to viral infection, the efficiency of viral replication, and as a result the progression and severity of virus-induced diseases. This review examines the ways in which the host-cell redox state affect viral replication and the actual potential of antioxidants to combat viral infections.