The present invention provides compositions comprising emulsion adjuvant and one or more active agents or substances formulated for infusion or injection into a subject (e.g., using a syringe and needle), as well as methods of formulating and using the same (e.g., as an injectable medicinal composition (e.g., a vaccine)). The emulsion adjuvant of an immunogenic composition of the invention in its preferred form comprises a cationic lipid containing a polar head group and a hydrophobic component (e.g., a dual chain hydrophobic group (e.g., the cationic surfactant dioctadecyl dimethyl ammonium chloride (DODAC) and dioctadecyl dimethyl ammonium bromine (DODAB))). Compositions of the invention comprising emulsion adjuvant and one or more active agents or substances formulated for administration via injection to a subject find use in treatment and/or prevention of infectious disease, cancer and/or allergy.