Treatment of 'I don't eat' condition (8)
I believe the answer is:
antidote
'treatment' is the definition.
(antidote is a kind of treatment)
'i don't eat condition' is the wordplay.
'condition' indicates anagramming the letters (I've seen 'conditions' mean this (letters must be in a new condition)).
'i'+'dont'+'eat'='idonteat'
'idonteat' anagrammed gives 'ANTIDOTE'.
'of' acts as a link.
(Other definitions for antidote that I've seen before include "It couneracts poison" , "Medicine countering a poison" , "Medicine to counteract poison" , "Agent counteracting a poison" , "simple remedy" .)