Purgative, emetic (5)
I believe the answer is:
enema
I believe this clue is a double definition.
'purgative' is the first definition.
(thesaurus)
'emetic' is the second definition.
(thesaurus)
(Other definitions for enema that I've seen before include "Medical liquid introduced anally" , "In the end medical procedure" , "Liquid injection given as a laxative" , "Colonic irrigation" , "Fluid injected rectally" .)