There's been a huge spike in the number of people dying from synthetic cannabis.
Provisional figures from the coroner show between 40 - 45 people died in the year since last June - in the previous five years there were two confirmed deaths.
The figures are causing doctors, families and the Drug Foundation to call for swift action to get it off the streets.
Synthetic cannabis was outlawed in 2014, and before that, it could be bought over the counter at the local dairy.
One ex-user, who wanted to remain anonymous, described what the drug did to her.
"You kind of just spin out, like you can't really move, you kind of just turn into a zombie," she said.
"You kind of just close your eyes and you're not really you anymore ... it makes you vomit sometimes."
She and her partner kept using it after it was made illegal, until one day things got too much.
"We couldn't find any. We'd run out and we had none left ... and I just lost it," she said.
"I was rolling around on the ground, like truly just screaming, ripping my clothes off myself and that was when my partner decided 'that's enough, we're not doing it anymore'."
St John Ambulance said it received about 30 callouts a week from people in trouble after taking the drug.
A doctor in the Wellington hospital's emergency department, Paul Quigley, said deaths were increasing because batches were becoming too potent for the body to handle.
The batches were manufactured from chemicals discarded by pharmaceutical companies, he said.
"The pharmaceutical companies are spending billions of dollars in trying to work out what parts of the cannabis plant could be used as a pharmaceutical drug to relieve pain, stop seizures, help people with a condition known as spasticity."
Those drugs were then thrown out by the companies, and picked up by the black market.
Dr Quigley said the first instance of this was back in 2006, but he said there had been a recent resurgence.
"It's very easy to get these agents from overseas in a liquid form. The cannabis market itself appears to be reasonably difficult and expensive at the moment and so the drug dealers are dealing in this much cheaper, easier to make and provide product."
He said manufacturers and dealers did not realise how strong these chemicals were and that they could cause users to suffer serious side effects including vomiting, seizures, hallucinations and arrhythmia.
Some users also reported suffering suicidal thoughts.
Harley Pataka killed himself in 2014 at the age of 23.
His mother, Katie Bayliss, said her son was a happy and well-loved boy, who enjoyed skating with his friends.
But that all changed when he became addicted to synthetic cannabis, she said.
"He became withdrawn, angry, a friend of mine told me that the weekend before he passed away she went over to where he was living and she walked in and she slapped his leg and he just looked at her as if he didn't even know who she was."
Where to next?
Ms Bayliss said her family had been ripped apart by the drug, which she said could be eradicated by the decriminalisation of marijuana.
The executive director of the Drug Foundation, Ross Bell, agreed.
"If we did have a regulated market for natural cannabis then we could have gone a long way to avoid, you know, many of these problems," he said.
"And even at the time when the country was having the big debate about legal highs there were lots of arguments saying that actually, you know, lets legalise natural cannabis to get rid of synthetic stuff."
Meanwhile, the Drug Foundation has also blamed a lack of action on the part of state agencies for the huge spike in the number of people dying.
Mr Bell told Morning Report today that Customs, police and the current and previous government have been made aware of the growing problem, but there's been no national co-ordination, information sharing or extra resourcing.
"There still has been no action, no co-ordination, no action from the top, no information-sharing between different government agencies so we know what's out there, no extra resourcing for treatment or outreach to these people. I'm appalled."
Mr Bell said it was vulnerable people on the margins who were dying and it was obvious where resources should go.
Paul Quigley from Wellington hospital's emergency department said he was not surprised at the jump, because batches of synthetic cannabis were becoming too potent for the body to handle.
He said they were made with chemicals discarded by pharmaceutical companies.
"The pharmaceutical companies are spending billions of dollars and trying to work out what parts of the cannabis plant that could be used as a pharmaceutical drug to relieve pain, stop seizures and help people with a condition known as spasticity."
Dr Quigley said the companies threw out ingredients from failed research and they ended up on the black market.
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