'Injecting disinfectant can make everything OK' initially baffled doctor (6)
I believe the answer is:
medico
'doctor' is the definition.
('medico' can be a synonym of 'doctor')
'injecting disinfectant can make everything ok initially baffled' is the wordplay.
'initially' says to take the initial letters.
'baffled' indicates anagramming the letters.
The first letters of 'injecting disinfectant can make everything ok' is 'idcmeo'.
'idcmeo' is an anagram of 'MEDICO'.
(Other definitions for medico that I've seen before include "Health practitioner" , "Doctor" , "quack" .)