Mike taken in by thin-sounding treatment (6)
I believe the answer is:
remedy
'treatment' is the definition.
(I know that remedy is a type of treatment)
'mike taken in by thin-sounding' is the wordplay.
'mike' becomes 'M' (phonetic alphabet: alpha, bravo, charlie etc.).
'taken in by' indicates putting letters inside.
'thin-sounding' becomes 'reedy' (I've seen this in another clue).
'm' inserted within 'reedy' is 'REMEDY'.
(Other definitions for remedy that I've seen before include "Antidote" , "Cure for disease or difficulty" , "Something that cures, disease or problem" , "Medicine or therapy to cure" , "Put right, be a cure for" .)