Police were called at 3.07am on Saturday, 31 July after a number of people were taken unwell at The Cause nightclub in Ashley Road, Tottenham.
Officers attended along with London Ambulance Service. A 21-year-old man was taken to hospital where he was subsequently pronounced dead. His next of kin have been informed.
The death is being treated as unexplained. A post-mortem examination will be scheduled in due course.
Two other men were also taken to the hospital where they remain in a stable condition.
At this early stage of the investigation, it is understood that all parties have taken drugs. At this stage, we don’t believe any persons were known to each other.
Superintendent Simon Crick, in charge of policing for Enfield and Haringey, said: “There is no safe way of taking illegal drugs, however, the incidents overnight have caused us particular concern. We urge anyone who bought drugs in or around the nightclub to dispose of these substances as soon as possible.
“An investigation is continuing to establish where these drugs have come from and I encourage anyone with information to contact police.
“If anyone has taken an illegal substance and becomes unwell then they should seek immediate medical advice.”
To report information about drugs and drugs supply call 101 quoting CAD 877/31Jul. You can also contact Crimestoppers anonymously on 0800 555 111.
Anyone who needs emergency medical attention should call 999.
No arrests have been made.