The medicine goes down (5)
I believe the answer is:
drops
This clue is a double definition.
'the medicine' is the first definition.
(thesaurus)
'goes down' is the second definition.
(dropping is a kind of going down)
(Other definitions for drops that I've seen before include "Gives up" , "treatment for eye" , "tiny amounts of medication" , "Falls" , "Abandons" .)