Course of treatment, say, taken by miner in a bad way (7)
I believe the answer is:
regimen
'course of treatment' is the definition.
(course of medical treatment)
'say taken by miner in a bad way' is the wordplay.
'say' becomes 'eg' (both can mean 'for example').
'taken by' indicates putting letters inside.
'in a bad way' is an anagram indicator.
'miner' anagrammed gives 'rimen'.
'eg' put into 'rimen' is 'REGIMEN'.
(Other definitions for regimen that I've seen before include "Recommended course" , "Therapeutic programme (of diet and exercise)" , "Mere gin for a course of treatment" , "That's what doctor orders" , "(In medicine) a systematic plan for therapy" .)