Allergen-specific immunotherapy, although efficacious, is now less frequently used because of potential adverse reactions. Recently, two new types of allergen immunotherapy have been developed that appear to overcome this problem, namely allergen gene vaccination and vaccination with allergen-immunstimulatory DNA conjugates. In animal models of allergy, both have been shown to induce nonallergic T-helper cell type 1 immune responses to allergens and downregulate pre-existing T-helper cell type 2 responses. In initial clinical trials with allergic patients, allergen-immunostimulatory DNA conjugates were well-tolerated, induced immunoglobulin-G but not immunoglobulin-E antibodies and appeared to have great potential as a novel, safe and efficacious type of allergen specific immunotherapy.