Rapid development of novel anti-hepatitis C virus (HCV) agents in recent years has greatly improved treatment outcomes. However, such rapid progress in anti-HCV treatment has not allowed us to fully argue the different characteristics of each anti-HCV agent, optimal multidrug combinations, and the selection of treatment enabling to efficiently eliminate drug resistant viruses. We here quantified the intrinsic antiviral effect of 15 anti-HCV agents either clinically available or under developmental phase using a cell culture system, and identified the parameters that represent the antiviral profile of drugs through mathematical analysis. A computer simulation that calculated the antiviral activity and the frequency of mutation rate under dual- and triple-multidrug treatment presented the argument for the advantage of multidrug treatments. In this review, we summarize the novel approaches to evaluate intrinsic antiviral efficacy of drugs by combining the virological and mathematical analyses.