The development of neutralizing antibodies to the protein drug interferon-β is a significant impediment to its use in the treatment of multiple sclerosis. Neutralizing antibodies to interferon-β arise from aggregation of the peptide during manufacturing and storage. We tested the ability of dodecylmaltoside, a nontoxic alkylsaccharide surfactant, to reduce aggregation of interferon-β in vitro and to reduce its immunogenicity in vivo. Interferon-β, in solution with and without dodecylmaltoside, was periodically evaluated for aggregation by light scatter for 1 month. Interferon-β, with and without dodecylmaltoside, was given 3 days/week for 1 month to mice; the sera of these mice were analyzed for anti-interferon-β antibodies by ELISA. Dodecylmaltoside reduces the aggregation of interferon-β in vitro and its immunogenicity in vivo. Our positive findings warrant additional tests of dodecylmaltoside as a therapeutic adjuvant in rodent models of multiple sclerosis.