Senior Sergeant Craig Dinnissen said last night police were called to assist St John at a party on Castle St about 11pm.
A 19-year-old man had taken MDMA and was "trying to scratch his eyeballs out", he said.
The drugs were tested and contained a low amount of MDMA, but a "huge quantity of bath salts".
The man was taken to Dunedin Hospital.
Snr Sgt Dinnissen said people needed to practice caution when it came to untested drugs, and preferably not take drugs at all.
"That's a huge risk . . . you're taking your life into your hands by popping pills that aren't prescription."
KnowYourStuff, who have worked in Dunedin previously, were not testing drugs in Dunedin this re-orientation week.
About the same time police were called to assist St John with crowd control after two "very drunk" students fell from a roof in the Queen St/Student area.
Both had minor injuries.
