London - A British tourist severed an artery while using a 72ft (about 22m) "extreme" waterslide.
Jade Graves, 29, lost four pints of blood and needed a transfusion as well as an operation to repair the blood vessel.
The incident happened on the Space Jam slide at Aqua Paradise Water Park in Nessebar, Bulgaria.
Graves said she followed advice from the lifeguard on duty to cross her arms and legs on the slide but at the end she felt intense pain in her lower pelvis and saw her legs "running with blood".
She became "faint and breathless" and was taken to hospital in nearby Burgas for surgery.
The bleeding led to haemorrhagic shock – when body cells are deprived of oxygen – and secondary anaemia.
The rupture to the artery in her groin is thought to have been caused by water pressure.
She said: "I still can’t believe what happened to me on that slide. I was meant to be having a lovely holiday with my family but the whole experience has been traumatising. I am still uncertain as to what happened exactly because I followed all the rules. I don’t want anyone else to have to go through what I have."
Graves, a mother of one, was on holiday with her mother Tina, brother Khalem Peacock and partner Simon Barrett. She spent four days in hospital in Bulgaria before being discharged and flying home to Hull. She had to take five weeks off from her retail job to recover.
She is now taking legal action against Aqua Paradise, which says on its website that its 25 slides are "the most modern type, ensuring security and reliability".
The 72ft Space Jam slide is listed as one of the park’s most intense, with two drops and a horizontal middle section.
It ends in a narrow half-tube filled with water rather than a plunge pool. Graves’s lawyers Irwin Mitchell said in a statement: "A young woman has sustained horrific injuries during what was meant to be a fun and relaxing time. Jade’s life has been completely turned upside down with her suffering mentally as well as physically."
The firm is aware of a least one previous injury on the same slide, involving a girl of nine, before Graves’s ordeal in July last year.
Swimmers can hit speeds of more than 48km/h on water slides and injuries around the world have included shattered limbs, ruptured organs and a broken neck.