There's limited evidence -- but no proof -- that face masks offer some protection against H1NI swine flu.

One study shows that when there's a sick family member in the house, other family members could cut their risk of getting sick by 60% to 80% by using face masks consistently and correctly -- in combination with frequent hand washing and avoiding close contact with the sick person.
 
Face masks rated as N95 masks -- technically called respirators -- should theoretically work better than surgical masks, which fit more loosely. But at least one study shows no difference in protection in household settings.

Ferret studies suggest that swine flu is spread by large droplets and not by small droplets. All face masks may protect against large droplets; N95 masks may protect against smaller, aerosolized droplets.
 
Studies consistently show that most people in household and community settings don't use face masks consistently or correctly.