WordNet (r) 3.0 (2006):

go to the dogs
    v 1: become ruined; "His business went to pot when economy
         soured" [syn: go to pot, go to the dogs]

Moby Thesaurus II by Grady Ward, 1.0:

35 Moby Thesaurus words for "go to the dogs":
   be ruined, become insolvent, break, bust, collapse, come down,
   crash, decline, degenerate, deteriorate, fail, fold, fold up,
   go bankrupt, go broke, go downhill, go into receivership,
   go to glory, go to hell, go to perdition, go to pot, go to ruin,
   go to shivers, go to smash, go to smithereens, go under, go up,
   go wrong, have a comedown, hit rock bottom, reach the depths,
   shut down, sink, slip, touch bottom