The unnamed 54-year-old fell out of his wheelchair on Sunday morning while he was the on the popular social networking site.
Without a phone, or his emergency call button nearby, the man decided to turn to Facebook to get help, getting the woman to call Calderdale Royal Hospital moments later.
The nurse who answered immediately contacted police who tracked him down to his home in the Luddenden Foot area of West Yorkshire using the social network.
Inspector David Shaw, who leads the West Yorkshire Police Valley South East Neighbourhood Policing Team, confirmed details of the incident.
He said: “At 9.24am on Sunday, police were made aware of concerns for the safety of a local man by a woman in Australia, who had been in contact with him through Facebook when he’d asked for help after falling.
“Officers confirmed the identity of the man and went to his home address to check on his welfare.
“When officers arrived the man, who lives in supported accommodation, was found to be fit and well but had initially asked for help after falling and not having his emergency pendant with him.
“In Calderdale we don’t deal with many enquiries from Australia so it was fairly unusual, but I’m glad we were able to help.”
Facebook is used by millions of people worldwide every day.