A notorious website has been criticised by charities for encouraging teenagers to share stories of eating disorders online.

Ask.fm, which has been accused of hosting cyberbulling that has led to suicides, has now been castigated for inviting online attacks on vulnerable youngsters by asking its teen users: "Have you ever thrown up after eating?"

Support group Anorexia Bulimia Care (ABC) said sites like Ask.fm, which is an anonymous question-and-answer forum where users ask each other often intimate questions, must safeguard young people's wellbeing.

A spokeswoman for ABC said: "It is imperative that sites such as Ask.fm take better responsibility, install monitoring procedures, and provide supportive resources through signposting to charities that can help."

A parent of one Glasgow teenager said she was "appalled" by the question posed on Ask.fm about vomiting after eating. The mother, who did not wish to be named, said: "Asking this question is leaving young girls open to all kinds of abuse. It is completely irresponsible - not to mention dangerous - for questions about eating disorders to be posted in this poisonous environment."

At least 1.1 million people in the UK are affected by an eating disorder, with young people aged between 14 and 25 most at risk.

Ask.fm, which has more than 70 million registered users worldwide, allows anyone to post anonymous comments about other users and has been heavily criticised for its lack of regulation.

Cyberbullying on the website has been linked to the suicides of as many as 12 young people around the world.

It sparked huge controversy after being linked to the suicide of Hannah Smith, 14, who was found hanged at her home in Leicestershire last August. After she died, her father found messages on the site urging his daughter to kill herself such as, "Go die, evry1 wuld be happy" and "No1 would care if ya died".

Hannah Smith's death is not the only one to be linked to bullying on Ask.fm. Izzy Dix, also 14, was found hanged at her home in Devon after suffering months of taunts. Her family say she took her life after struggling to cope with cruel comments, often via Ask.fm. Her devastated mother Gabbi believes a strong response is needed and she has gathered more than 114,500 signatures for an online petition calling on the Government to outlaw the site.

"Izzy was bullied at school and in the community over a period of about 18 months", she said. "She would be relieved to get home from school but then the abuse continued online. Bullying is relentless these days. There is no break from it."

The suicides of two Irish teenage girls, Ciara Pugsley, 14, and Erin Gallagher, 13, and two boys from Lancashire, Josh Unsworth, 15, and 16-year-old Anthony Stubbs, were also said to have followed online attacks.

In the wake of their deaths major advertisers - including Specsavers, Vodafone, Laura Ashley and charity Save the Children - pulled out of the site, intensifying pressure on the Latvian owners to clean up their act.

Ask.fm claimed the question about eating disorders was originally posted in Russian and its meaning lost in translation.

A spokeswoman for the website said: "This question appeared on our site due to a translation error, which meant its initial meaning was lost. We apologise to all users who found this question upsetting."

Elaine Chalmers, area manager for ChildLine Scotland, said websites must take responsibility on the issue of bullying on such sites.

She said: "All websites have a duty of care to their users, especially if they are children. Just as a school takes responsibility for what happens within its gates, social networking sites must take more responsibility for the content and conduct on their sites."