An antibody preparation suitable for intravenous administration in humans includes IgG, IgA and at least 5% IgM antibodies by weight of the total amount of antibodies. The preparation is prepared from human plasma, has specific complement activating activity, and, in an in vitro assay with human serum suitable to determine the ability of the antibody preparation to activate complement unspecifically, the antibody preparation generates substantially no C5a and/or substantially no C3a. The antibody preparation can have medical uses.
