Endo Cave hydrate is a new type of cyclopentylguanosine anti HBV drug. Its pharmacological action is similar to that of entredo Cave. It is clinically suitable for the treatment of chronic hepatitis B with active viral replication, elevated serum aminotransferase ALT or liver histology showing active lesions. This product is guanine nucleoside analogue and has inhibitory effect on hepatitis B virus (HBV) polymerase.