K2 is the most toxic and harmful of the synthetic cannabis products he has witnessed in patients, a Dunedin Hospital emergency department specialist says.
Dr Bruce Lambie said K2 - which is being tested by health authorities with an eye to banning it - had caused trouble in the department for the past three months.
"It's been quite a problem here."
K2, the worst of the synthetic cannabis products he had seen, caused hallucinations, agitation, seizures and "violent aggression".
About three weeks ago, an ED patient under its effects assaulted a security guard, Dr Lambie said. Police were called to that incident.