An inquest into the drug overdose of a Perth teenager is examining whether qualified ambulance paramedics should be required to attend large music festivals.

Gemma Thoms, 17, died in hospital the day after taking three ecstasy pills before she entered the Big Day Out festival in February 2009.

The inquest has heard she took two of the pills at once because she was concerned they would be found by police sniffer dogs.

A friend told the Perth Coroners Court that Ms Thoms did not seem herself after taking the tablets.

Cassandra Southern testified that both of them became hyperactive and fidgety, but Ms Thoms was also very tense, chattering her teeth and jumbling her words.

Soon after, she was taken to the first aid tent, where she was assessed by volunteers, because she looked sick.

Ms Thoms was allowed back into the crowd after asking to leave and because she was wearing a wrist band, given to her at the festival's entry, indicating she was over 18.

The inquest has heard she may not not have been allowed back into the festival if the first aid volunteers had known she was only 17.

The Coroner has been asked to consider whether fully qualified ambulance paramedics should be required to attend all large scale concerts such as the Big Day Out.

Outside the inquest, Ms Thoms' mother, Peta Davies said she hoped her daughter's death would serve as a warning to all involved in music festivals.

"It'll be a good thing to remember Gemma by that everything has been done possible to make sure future events are ok," she said.

"We really want to make sure that the care given at the Big Day Out was the best that could be done.

"Maybe the possibility of having future paid paramedics at events like that so we'll just see, just see what happens."

The inquest is set down for five days.

