Celia Hatton. Photo: Supplied.
Ketamine is a hallucinogenic drug originally developed as a medical and veterinary anaesthetic, that's also used recreationally.
According to the Drug Foundation recreational use of ketamine is relatively low here in New Zealand, where it's classified as a Class C drug.
But is an emerging problem in China, where seizures of the drug are rocketing and organised criminal gangs have perfected ways to make ketamine themselves.
The BBC's Celia Hatton has been investigating China's ketamine problem, and the global trade in the drug.