PURPOSE: To provide the titled composition having low irritancy to the nasal mucous membrane and little ill odor, and composed of a lower alkyl ether of cellulose, beclomethasone dipropionate and an odorless solid organic acid as a stabilizer.

CONSTITUTION: A stabilized powdery drug composition for the application to the nasal mucous membrane, is prepared by compounding (A) a lower alkyl ether of cellulose (e.g. hydroxypropylcellulose) preferably having a water-content of 3W 9wt%, (B) beclomethasone dipropionate which is a steroidal anti-inflammatory agent, and (C) an odorless organic acid solid at normal temperature (e.g. stearic acid, palmitic acid, etc.) as a stabilizer. The particles having an effective particle diameter of about 20W250μ acount for preferably ≥90wt% of the composition. Dose for application: 5W200mg per dose. It is suitable for the treatment of allergic rhinitis, vasomotor rhinitis, etc.