Arbidol Hydrochloride (Arbidol HCl) is an antiviral medication used to treat and prevent influenza, respiratory syncytial virus (RSV) infection, and other viral respiratory infections. It is known for its broad-spectrum activity against various types of viruses, including influenza A and B viruses, hepatitis C virus, and others. Arbidol HCl is believed to exert its antiviral effects by inhibiting the fusion of the viral envelope with host cell membranes, thereby preventing viral entry and replication.