Rehab regimen (5)
I believe the answer is:
detox
'rehab regimen' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for detox that I've seen before include "Treatment for alcoholism" , "undergo treatment for addiction" , "Remove poisons from the body" , "Removal of bodily poisons" , "possible treatment of alcoholic" .)