Pharmaceutical composition for treating hepatitis B and heath food for inhibiting hepatitis B virus

The invention provides a pharmaceutical composition for treating hepatitis B, including: an effective amount of proanthocyanidins oligomer; and a pharmaceutically acceptable carrier or salt, wherein a formula of the monomer of the proanthocyanidins is shown in the following: and wherein R1 is OCH3, R2 is OH and R3 is H, or R1 is OH and R2 and R3 both are H, or R1 and R2 both are OH and R3 is H, or R1, R2 and R3 all are OH, and R4 is 3-( )-OH, 3-( )-OH, 3-( )-O-sugar or 3-( )-O-sugar. Bonding between adjacent monomers take place at C4, C8 Carbon-carbon bond or C2, C7 oxygen bond of A type or C4, C8 or C4, C6 Carbon-carbon bond of B type or C type of proanthocyanidins. And the polymerized number is from 2 to 30.