Your doctor has instructed you to rinse your mouth after using your inhaler in order to gently wash away any medicine particles that were not inhaled into the lungs and may have remained behind in your throat. It is especially important to rinse your mouth after each use of any of the daily-use maintenance anti-inflammatory inhaled corticosteroid (ICS) preparations, whether administered by MDI, DPI, or nebulizer.
The inhaled corticosteroid medications can, if they land in your throat, cause some throat irritation, and occasionally lead to a yeast infection in the mouth or throat called thrush. Rinsing your mouth and gargling is thought to reduce your chances of getting thrush and decreases the chance that you will experience throat irritation or hoarseness. Remember to rinse and then spit; do not swallow the liquid you gargled with!