The family of an "amazing" 16-year-old who died at a house party have paid tribute to her.
Kayleigh Burns, who was asthmatic, collapsed at the gathering in Leamington Spa, Warwickshire, on 4 June.
Her family have since said they were sent videos of Kayleigh inhaling nitrous oxide the night of her death, before she later complained of feeling "too hot", then collapsing and being taken to hospital.
Kayleigh's cause of death has not been confirmed.
Her sister, Clare Baker, 31, said she was messaged by a friend of Kayleigh's to say she had been taken to hospital, and she began ringing around hospitals in the area to find where she was.
But Merseyside Police came to her home later the same day to tell her Kayleigh, who was just weeks away from turning 17, had died.
Clare, from North Liverpool, said: "My sister was only 16, almost 17, and she was the most amazing little girl ever. The bond that we had, I can't even describe.
"Kayleigh grew up and had a good childhood and she was in a loving family. As she grew older she got mixed up with the wrong sort of people.
"She was interested in make-up and fashion and wanted to travel the world. She wanted to be an air hostess or work on the cruises and her life was taken away from her."
Clare said Kayleigh moved to Coventry to live with her girlfriend, before moving to Leamington Spa.
She had come to visit her family a week before her death.
Clare told The Liverpool Echo: "I will be missing a huge piece of my heart for the rest of my life now and I don't know how I'm going to go on without her. But I need to because I have kids.
"I want people to think about what they are taking before they take it because they're going to leave people behind who love them. People may think it is a laugh and a joke, but it's not, they're playing with their lives.
"I want it (nitrous oxide) to be banned. They have upped the legal age of buying it in America today to 21. I know people use it in the food industry, but I think there sound be some sort of ID card or at least an age requirement."
According to FRANK, the information and advice website, taking too much laughing gas can lead users to either faint, lose consciousness, or suffocate from lack of oxygen.