Ribavirin can inhibit the growth of respiratory syncytial virus, influenza virus, hepatitis A virus, adenovirus and other viruses in vitro, but its mechanism is not fully understood. Ribavirin did not alter viral adsorption, invasion, or molting, nor did it induce interferon production. Ribavirin enter the cells infected by the virus rapidly phosphorylation and its product as competitive inhibitors of virus synthetase, inhibition of inosine monosodium phosphate dehydrogenase, influenza virus RNA polymerase and mRNA guanosine transferase, causing cell guanosine triphosphate, damage the virus RNA and protein synthesis, inhibition of viral replication and spread. It may also have immune and neutralizing antibody effects on respiratory syncytial virus. Drug metabolism: The concentration of ribavirin in respiratory secretions was mostly higher than that in blood. This product can enter the red blood cell, and the accumulation of large. The concentration of drugs in cerebrospinal fluid can reach 67% of the blood concentration in the same period after long-term medication. This product can cross the placenta, can also enter the milk. It's metabolized in the liver. Intravenous administration eliminated tl/2 in about 0.5-2 hours. It is mainly excreted through the kidney. The urine excretion rate is 30%-55% at 72-80 hours. The fecal excretion rate in 72 hours is about 15%. The drug can accumulate in red blood cells for weeks.