When poison-free, would exact diet do otherwise? (11)

I believe the answer is:

detoxicated

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'when poison-free would' is the definition.
I can't tell whether this defines the answer.

'exact diet do otherwise?' is the wordplay.
'otherwise?' indicates an anagram (I've seen 'otherwise' mean this).
'exact'+'diet'+'do'='exactdietdo'
'exactdietdo' is an anagram of 'DETOXICATED'.

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I've seen this clue in the Sydney Morning Herald.

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