Wellington Hospital's emergency department has had a surge in patients needing treatment after taking the hallucinogenic drug LSD.
The hospital says last year it would see a patient under the influence of LSD only about once every six months but since January this year, it has been admitting one or two every weekend.
The hallucinogenic drug fell out of favour in the early 2000s when Ecstasy became more popular with recreational drug users.
But an emergency medicine consultant at Wellington Hospital, Paul Quigley says more young people are using it as the quality and reliability of available Ecstasy wanes.
Dr Quigley says more people are arriving at the emergency department experiencing anxiety, insomnia and hallucinations so strong they find it difficult to communicate what is wrong.
Chris Wilkins from Massey University's drugs research unit says his own research suggests a trend towards more LSD use in other main centres too.