Quack medicine (7)
I believe the answer is:
nostrum
'quack medicine' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for nostrum that I've seen before include "Simple, remedy" , "Quack medicine - run most (anag)" , "answer to all problems!" , "Supposed remedy" , "Panacea or cure-all" .)