Abstract: Compositions and methods can be used for tolerizing the immune system. The compositions can be physiologically acceptable and can include any of a wide variety of allergens that are designed to be administered in escalating doses to, for example, an infant. The compositions can include other active ingredients (e.g., one or more of a steroid, vitamin, mineral, vasodilator, hormone, decongestant, anticholinergic agent, leukotriene inhibitor, immunomodulator, mast cell stabilizer, expectorant, immune suppressant, anti-histamine, or anti-inflammatory agent) and/or a carrier.