Drug squad detectives are investigating any link between pills which put six Hamilton girls in hospital and an alleged criminal syndicate in Auckland which made tens of thousands of designer drug tablets each week.
The Fairfield College pupils, as young as 13, swallowed the pink pills at school, which ledthem to react aggressively when admitted to Waikato Hospital's emergency department.
Health professionals believe the abusive behaviour - inconsistent with Ecstasy use - was caused by man-made chemicals such as mephedrone mixed into Ecstasy tablets.
And mephedrone is among the chemicals allegedly mixed into tens of thousands of pills each week by a drug ring busted by police last week.
Detective Inspector Bruce Good, head of the Auckland metro drug squad, confirmed he had contacted police colleagues in the Waikato after the schoolgirl scare on Monday.
Once ESR tests on the Fairfield college pills were complete, Mr Good said the results would be compared with the tablets seized in the 12-month Operation Ark which led to 21 arrests and $14 million of assets being frozen last week.
"My team are going through the mountain of stuff we have. Once ESR has completed the report [in Hamilton], we'll ... see if any links exist."
When announcing the Operation Ark arrests 10 days ago, Mr Good said the alleged syndicate was responsible for 80 to 90 per cent of the Ecstasy market in New Zealand.
But Mr Good said manufacturers were "tweaking" the molecular structure of the pills, which contained Class-C drugs like mephedrone, as well as the usual MDMA found in Ecstasy.
"Those who've been manufacturing such pills have modified the molecular structure of various compounds and, by so doing, created dangerous substances that have been sold as Ecstasy.
"You cannot ignore the dangers. If someone puts an Ecstasy tablet in your mouth, you don't know where it's come from, the structure of it and what effect it might have.
"These people are tweaking the structure on a very regular basis. My advice to anyone putting Ecstasy in their mouth: don't."
The reaction of the Fairfield students is similar to an incident in which "Red Rocket" pills landed six people in hospital in one weekend in September. Staff at Middlemore Hospital were shocked by the violent seizures and hallucinations.
National Poisons Centre toxicologist Dr Leo Schep said there had been a number of calls from health professionals asking about the drugs.
Dr Schep said that in rare cases people overseas had died after taking mephedrone.
