The phrase 'to the dogs' has been used since the 16th century to mean 'ruined'. It is based on the idea that some food item perhaps that is beyond human use is fit only to be thrown to the dogs of the household. Shakespeare in 'Macbeth' writes: "Throw physic to the dogs; I'll none of it." The earliest-recorded use of 'go' to the dogs appeared in 1619.
