On Friday, Wellington Police attended five incidents where individuals were believed to have overdosed on a substance that is thought to be GHB, commonly known as fantasy or liquid ecstasy.

One person has died and three others remain in hospital after five cases of GHB overdose in Wellington on Friday.

Police said the fifth person has been treated and discharged from medical care.

Inspector Wade Jennings said the patients had overdosed on a substance thought to be GHB, commonly known as fantasy or liquid ecstasy.

“An investigation is underway and Police are treating the matter as a priority given the risk to the public,” Jennings said.

He said the incidents happened across the district – in Miramar, Brooklyn, Johnsonville and Upper Hutt.

“Police are urging the public to exercise caution, and anyone who may have this type of substance [is] urged not to consume it.

“If you, or someone you know, are feeling unwell, please go to your nearest healthcare provider urgently.”

According to the NZ Drug Foundation, GHB – or gamma hydroxybutyrate – is a depressant drug with a strong sedative effect. It is “active in very small amounts” and is easy to overdose on.

The foundation’s informational platform, The Level, said signs of an overdose include severe muscle jerks or tremors, losing control of body movements, choking on vomit, difficulty breathing, chest pains, becoming unresponsive or losing consciousness, experiencing psychosis, and seizures.

“You or the people around you should act quickly. Call 111,” it said.

If it is an emergency and you feel like you or someone else is at risk, call 111.