Abstract: Macrolide formulations, such as an erythromycylamine formulation, for delivery by aerosolization are described. The concentrated erythromycylamine formulations contain an amount of erythromycylamine effective to treat infections caused by susceptible bacteria. Unit dose devices having a container containing a formulation of the macrolide antibiotic in a physiologically acceptable carrier are also described. Methods for treatment of pulmonary infections by a formulation (liquid solution, suspension, or dry powder) delivered as an aerosol having mass median aerodynamic diameter predominantly between 1 to 5 &mgr;m are also described.