WordNet (r) 3.0 (2006):

go to pot
    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:

43 Moby Thesaurus words for "go to pot":
   be ruined, become insolvent, break, bust, collapse, come down,
   come to naught, come to nothing, crash, decline, degenerate,
   deteriorate, dissipate, fail, fold, fold up, go bankrupt, go broke,
   go downhill, go into receivership, go to glory, go to hell,
   go to perdition, go to ruin, go to seed, go to shivers,
   go to smash, go to smithereens, go to waste, go under, go up,
   go wrong, have a comedown, hit rock bottom, leak, leak away,
   reach the depths, run to seed, run to waste, shut down, sink, slip,
   touch bottom