Police said the woman, who was at the Midnight Mafia dance party at Olympic Park in Homebush, was taken to Concord Hospital about 2:30am. She is in a stable condition.
Four people suspected of taking illegal drugs at music festivals in New South Wales have been taken to hospital in the past two days.
A 19-year-old man, who is also suspected of using drugs at the same festival, has been released from hospital.
Police said 18 people were arrested for drug-related offences at the event, including 16 for drug possession – with 12 of those being the possession of MDMA, also known as ecstasy.
Seven people have died after allegedly taking drugs at music festivals across Australia in the past 12 months.
A group of doctors are planning to roll out pill testing at music festivals, after Premier Mike Baird said he would never support the practice, saying it would condone drug use.
Auburn Police Inspector Stuart Sweeney said he wanted to remind people that taking drugs was not safe.
“I think it’s evident by the fact that a number of people have been taken to hospital suffering what we believe to be overdoses,” Inspector Sweeney said.
“I think the clear message is: don’t take the drugs … you don’t know what you’re dabbling with.”
Police said they conducted 111 drug dog searches of festival goers at Olympic Park.
On Saturday another woman was admitted to John Hunter Hospital for a suspected drug overdose after she was found unconscious at the Groovin the Moo festival in Maitland.
Paramedics took her to hospital in a critical condition. Another teenage male who was also taken to hospital for drug use at Groovin the Moo has been discharged.