The origin of this expression is believed to be in ancient China where dogs, by tradition, were not permitted within the walls of cities. Consequently, stray dogs roamed the areas outside the city walls and lived off the rubbish thrown out of the city by its inhabitants. Criminals and social outcast were often expelled from cities and were sent to live among the rubbish – and the dogs. Such people were said to have “gone to the dogs”, both literally in that was where they were now to be found, and metaphorically in the sense that their lives had taken a distinct turn for the worse.
