A surgical mask is intended to be worn by health professionals during surgery and at other times to catch the bacteria shed in liquid droplets and aerosols from the wearer's mouth and nose.
Outside health care facilities, simple, inexpensive masks of similar appearance are commonly worn in heavily populated centres in East Asia to help prevent spreading the common cold. In Japan, it is common to wear a face mask while sick to avoid infecting others in public settings.
Surgical masks were widely used in China, Hong Kong, Vietnam, and Toronto, Canada during outbreaks of the SARS virus, during the 2007 avian bird flu pandemic in Japan, and more recently in the United States and Mexico City during the 2009 H1N1 flu outbreak, also known as the swine flu.
Modern surgical masks are made from paper or other non-woven material, and should be discarded after each use.