A toxic substance released in a Melbourne nightclub overnight has left at least one person in hospital.
Police were called to the Perseverance Hotel on Brunswick Street, Fitzroy around 1am on Sunday morning following reports of an assault, but instead attended to a medical emergency.
Fifteen people were treated at the scene by paramedics after inhaling the mystery substance.
A 27-year-old man was arrested for assault related charges but he has since been released.
The substance and means of release remain under investigation.
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