Dreams of decay symbolize that you have allowed an aspect of your upkeep to slip. Perhaps you have allowed negative thoughts and/or behavior to fester. Your subconscious mind is alerting you take care of yourself and take the action necessary to bring you back into balance.
Psychological / emotional perspective: When something is decaying it is running out of energy.
For it to appear in dreams indicates we must be prepared to allow things to run their natural course. Putrefaction is when the process of decay has gone past the point of no return.
Material aspects: In mundane terms, we have a situation in our lives – perhaps a work project or a relationship – that has come to a natural conclusion and does not need to be nurtured.
The experience we have gained, however, can be put to good use.