Not for that issue - and while scientifically an herb, most people do think of it as a drug (and it sure is, just not "traditional" medicine).
But have had some success with cannabis for retention - Doctor says that's because while I have no feeling as far as when it's full due to nerve damage, the actual muscle still tightens up (that is what causes my retention), but that stuff does relax it.
Somehow I don't think that is going to do you any good though.