A potentially lethal alternative to the party drug, MDMA, is flooding the New Zealand market in the wake of Covid-19 affecting global supply chains.
The drug-checking agency, Know Your Stuff, said testers had seen a big jump in the amount of eutylone masquerading as MDMA this year.
At least two people, including one having seizures, needed emergency medical treatment.
Spokesperson Jez Weston warned that eutylone could cause vomiting, psychosis, convulsions and even death.
He said it was impossible to tell the difference between the drugs by sight or smell alone, and no one should take a drug without testing it.
"We know that Covid has affected global supply chains for all sorts of different products and MDMA is just the same.
"So what's being sold in New Zealand is what's available in New Zealand which is these nasty cathinones."
At-home testing kits were not as good as the testing process Know Your Stuff provided, but they were better than nothing, he said.