Abstract: On the basis of the present invention in relation with inhibiting hepatitus B virus replication, the pharmaceutical preparations containing the iridoid compounds are represented by the following structural formula(1), wherein, R1 is H or OH,R2 is H or COOR6 (R6 is H or lower alkyl),R3 is H or .beta.-D-glucose,R4 is OH, CH.sub.2 OH or 4-phenylpropionyloxy group,R5 is H, OH or O-glucose,C7-C8 shows single bond or double or ##STR1## (epoxy bond) In the above formula, the compound indicates Aucubin, Catapol, Geniposide, Rehmannioside, Harpagoside, Harpagide and Genipin.Meanwhile, Gardenoside and Swertiamarin such as other iridoids mentioned above are also expected to produce antiviral effect on HBV replication, since they possess the similar chemical structure and other pharmacological characteristics such as liver-protective activities against hepatic damages caused hepatotoxic substances and inhibitory effects on RNA and protein biosyntheses.