Ten Arabs concocted arsenic poison (8)

I believe the answer is:

ratsbane

'arsenic poison' is the definition.
(ratsbane is a poison containing arsenic)

'ten arabs concocted' is the wordplay.
'concocted' indicates an anagram.
'ten'+'arabs'='tenarabs'
'tenarabs' is an anagram of 'RATSBANE'.

(Another definition for ratsbane that I've seen is " Poison for rodents".)

I've seen this clue in The Guardian.

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