The SARS-Cov-2 Mpro is structurally similar to Ritonavir, and Liponavir-Ritonavir, has been examined in inhibiting Mpro, the latter of which is in the class of proteases that it binds to. The docking score is 100.37, which appears reasonable when compared to Nirmatrelvir's score of 68 or 70.7. However, as mentioned, Ritonavir is large and flexible and can generally interact and fit somewhat to general proteases and proteins. Upon inspection of the docked Ritonavir to Mpro, it extends into one X-cave and the surface tunnel. It partly enters another X-cave and covers over, not in, the 3 rd cave. It possibly enters the target region necessary to inhibit biochemical viral replication. This is a good example of why localization of small molecule to the protein is more important than a high docking score in realistic molecular design, however both being important. Ritonavir was found in conjunction with Liponavir, and also in other combinations, not to be an effective drug in blocking the SARS-Cov-2 .