11 across
Recalling
upset
about
drug
producing
bad
reaction
(10)
Recalling upset about drug producing bad reaction (10)
hints
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hints
The definition is at the end of the clue.
How the clue works
Look at producing bad reaction at the end — that's your definition. Take the letters of Recalling and add E (the drug, ecstasy), then "upset" signals you need to jumble the whole lot together to get your answer.