A cure gone wrong creates stir (9)
I believe the answer is:
encourage
'stir' is the definition.
(thesaurus)
'a cure gone wrong' is the wordplay.
'wrong' indicates anagramming the letters.
'a'+'cure'+'gone'='acuregone'
'acuregone' with letters rearranged gives 'ENCOURAGE'.
'creates' acts as a link.
(Other definitions for encourage that I've seen before include "Recommend" , "Give hope to (someone)" , "Give hope or confidence to, help to advance" , "Cheer" , "Give support, confidence or hope to" .)