Abstract: The invention discloses the use of low molecular weight hyaluronic acid fragments, which can be suitably modified, where appropriate, for producing vaccines. The vaccines are particularly suitable for controlling cancer diseases. Surprisingly, it has been found that low molecular weight hyaluronic acid fragments, which can be suitably modified, where appropriate, can be used both for preparing mature dendritic cells and directly, together with antigens or peptides or carrier systems, as an adjuvant in vaccines. It is likewise possible to couple the low molecular weight hyaluronic acid fragments, which can be suitably modified, where appropriate, to an antigen, peptide or carrier system. The coupled system can then be advantageously employed as a vaccine, in particular for treating cancer diseases.