At least five people have reportedly fallen ill after drinking – yes, drinking – poppers at Manchester’s Parklife festival.

Greater Manchester Police said four people have been discharged from North Manchester General Hospital, but a 26-year-old woman is still being treated. Her condition is not known.

Officers seized 400 bottles of poppers at the festival over the weekend. Chief Inspector Gary Simpson said: “We are now extremely concerned that people are drinking poppers and this poses a significant risk to life and would urge anyone using, or considering using them or any ‘legal high’ to cease from doing so immediately, before it’s too late.”

Parklife warned punters not to consume the drug after hearing the reports on Saturday. A spokesperson tweeted: “Please be aware poppers are being misused as shots. Don’t consume anything not sold from our bars, if you do seek medical advice immediately.”

Poppers, often known by brand names like Liquid Gold and Rush, contain alkyl nitrites which dilate the blood vessels and cause a head rush when sniffed.

Disclosure, Fatboy Slim and Rudimental were among the acts playing the two-day festival at Heaton Park. There were 55 arrests across three days but no major incidents, police said. [via Independent]