Apparently this has been Australian government policy for some years now, but I'd never seen the results first-hand before. Here are the backs of two packs of cigarettes -- one of Pall Mall, one of Winfield -- I saw today on a restaurant table in Sydney. Click for larger and more gruesome.
The Australian regulations say that 30% of the front of a cigarette pack, and 90% of the back, must be used for health warnings, including pictures of body parts with cigarette-related diseases. The last time I remember seeing a picture of a gangrenous foot was when leafing through some of my dad's medical textbooks when I was a kid. Whether this works as a public health measure I don't know -- but, wow. Meta-point: a dependable payoff of traveling around is seeing the surprising small details in which national practices differ.