A QR (Quick Response) Code is a two-dimensional matrix/bar code created in 1994 by Japanese corporation Denso-Wave for inventory purposes.
Users hold their phone up to the code displayed on a sign, in a book, on a computer screen, tv, or almost anywhere. The phone camera snaps the code and takes the user to a website with more information – no typing needed – just point and click.
QR Codes are most common in Japan where they are currently the most popular type of two dimensional codes. Most Japanese mobile phones can read this code with their camera. (definition courtesy of Mashapedia = wikipedia and Mashable)
For healthcare think: detailed information on drugs, facilities, services advertised in magazines, tv, signs and billboards.
How about a QR attached to a GPS to direct travelers to the closest emergency room?