The mystery drug that put nine backpackers in Perth hospitals has been identified as a prescription medication commonly used to treat motion sickness, but also illicitly used as a date rape drug.
Emergency crews arrived at Colombo Street in inner-city Victoria Park on Tuesday night, to find some of the group unconscious, while others were suffering seizures after taking the then unknown substance.
It is believed the drug, now identified as hyoscine, arrived in the mail posted from New York and was addressed to someone who had never lived at the residence.
Another name for the substance is scopolamine, or “scoop” which could explain why the slang word was written on a piece of paper the package was wrapped in, police told 7 News.
The backpackers were rushed to three different hospitals. Those affected were seven men and two women, aged 21 to 25 - five French citizens, two from Germany, one Italian and one Moroccan.
Two men are in a critical but stable condition at Royal Perth Hospital, while one woman is stable at St John of God Hospital.
Police said in extreme cases the drug could cause hallucinations, overheating, paralysis, and multi-organ failure, resulting in many fatal overdoses, and it was a miracle none of the nine had died.
The backpackers allegedly opened the parcel and, thinking it was cocaine, divided it into nine lines before snorting the substance.
They suffered hallucinations immediately, and within 10 minutes they were almost all unconscious.
Royal Perth Hospital emergency doctor David McCutcheon said the patients arrived hallucinating, ill and in a state of agitated delirium and, most seriously, had racing hearts and overheating bodies.
Three were put into induced comas and were in intensive care "for their own protection", he said.
Royal Perth Hospital clinical toxicologist Jessamine Soderstrom said overheating bodies were eventually fatal.
"You go into multi-organ failure and patients die from that," she told reporters.
"If it wasn't for the timely call of the resident, some of those patients inevitably would have died."
She urged people to immediately ring Triple-0 if they were concerned about someone who had taken an illegal drug.
One of the backpackers, who returned to the house on Wednesday, told reporters he had felt like his face was "melting off" and that he had tried to scream but his mouth would not open.
Neighbours described a scene in which the young people were wheeled out on ambulance stretchers, with "glassy eyes" and one man behaving aggressively, punching at the air.
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The couple who own the property attracted the attention of the Victoria Park local government, with council officers visiting on Wednesday and investigating if it was being illegally used as a backpacker hostel.
Health Minister Roger Cook said the prospect of a "bad batch" of drugs in Perth was worrying.
He said there was no such thing as a safe, illegal drug and the government was committed to reducing supply and demand through law and order and education.