A grieving mother has revealed that her 18-year-old daughter died at the Mutiny Festival in Portsmouth after taking two pills.
Janine Milburn, a healthcare assistant, said Georgia Jones "was 18 and full of life" and that she hopes "this stops at least some of you ending up the same".
The popular dance festival has been cancelled as a "safety precaution" after the death of Ms Jones and a 20-year-old man.
The two who died and another who is in critical condition were among 15 people to attend hospital during one night of the Mutiny Festival.
The deaths are being treated as separate incidents and are not being treated as suspicious. However, Hampshire Constabulary said inquiries were being made to determine the circumstances.
Organisers said on Saturday night they were aware of "dangerous high strength or bad batch" of drugs on site.
The festival said in a statement: "Following the terrible news from earlier today, the team behind Mutiny Festival are incredibly sad to announce that the Sunday of the festival has been cancelled as a safety precaution.
"The safety of our amazing customers has always been paramount to us and so to keep everyone safe and in respect to those who have passed, we have taken the decision not to open today. As you can imagine, this decision was not taken lightly and was taken with the support of the local statutory authorities who we continue to work with.
"Enquiries are being made into the circumstances of what has happened, but we must reiterate our advice to all our customers to responsibly dispose of any substances.
"More information will follow when available, we appreciate your understanding at this difficult time."
Dizzee Rascal, Craig David and Sean Paul topped the bill at the two-day event that was due to end on Sunday.
Police were first alerted to the woman falling ill at the site on Saturday evening and the man was found collapsed around 20 minutes later.
Earlier on Saturday evening, Mutiny Festival tweeted a post entitled "Harm prevention alert", which said: "Festival family - we are aware of a dangerous high strength or bad batch substance on site.
"We strongly urge you to not take any substances whatsoever and to report any symptoms of illness / discomfort immediately to medical, welfare, security or the safeguarding team.
"Please stay alert and look out for each other."
In response to the post, Hampshire Police told Sky News: "We are aware of the alert issued by the festival and are looking into its content."
A woman has posted on social media paying tribute to her 'little girl' who 'died after taking two pills' to warn others about the dangers of drugs.
Janine Milburn, from Havant, said this morning Georgia Jones suffered a 45-minute fit after taking the pills.
Mrs Milburn said "my little girl was 18 and full of life" and "I just hope this stops at least some of you ending up the same".
The post read: "As I have now spoken to family members I can now say Georgia died yesterday due to complications after taking two pills at Mutiny.
"If nothing else I hope what has happened to her will deter you from taking anything ever."
She continued: "The pills had caused her temperature to rise so high it made her fit for 45 mins.
"My little girl was 18 and full of life, I just hope this stops at least some of you from ending up the same."
Police have appealed for anyone with information to come forward.
The force said: "At 7.10pm on Saturday 26 May, we were informed that an 18-year-old woman had fallen ill at the festival site in King George V Playing Fields, Cosham.
"The woman was taken to Queen Alexandra Hospital where she later died.
"At 7.30pm, a 20-year-old man was found collapsed at the festival site. He was taken to Queen Alexandra Hospital where he later died.
"The deaths are being treated as separate incidents at this stage. They are not being treated as suspicious but inquiries are being made to determine the circumstances of what happened in each case."
The force said next-of-kin for both the woman and the man had been informed and were being supported by specialist officers.
Anyone with information is asked to contact police on 101.