A respirable dry powder can include acetylsalicylic acid in particles having a mass median aerodynamic diameter (MMAD) within a range of about 0.5 μm to about 10 μm. The respirable dry powder may contain a pharmaceutically acceptable excipient, such as an amino acid (e.g., Leucine), in an amount ranging from about 0.1% (w/w) to about 40% (w/w) of the particles.