It is intended to provide a therapeutic agent or preventive agent for hepatitis which comprises a novel immune-stimulating oligonucleotide and interferon-ß in combination and has an enhanced interferon (IFN)-inducing activity and a reduced inflammatory cytokine-inducing activity. The invention provides the therapeutic agent or preventive agent for hepatitis comprising as active ingredients interferon-ß and an oligonucleotide (provided that an oligonucleotide having a nucleotide sequence represented by SEQ ID NO: 5 in the sequence listing is excluded) having a full length of 16 to 37 nucleotides represented by the formula (1): 5'-(G)MPXCGYQ(G)N-3' [wherein C represents cytosine, G represents guanine, X and Y each independently represent a nucleotide sequence having a length of 0 to 10 nucleotides without containing 4 or more consecutive guanines (provided that a length of X+Y is from 6 to 20 nucleotides), XCGY represents a nucleotide sequence having a length of 8 to 22 nucleotides including a palindromic sequence having a length of at least 8 nucleotides, P and Q each independently represent one nucleotide other than guanine, M represents an integer of 6 to 10, and N represents an integer of 0 to 3].
