Facebook is allowing videos showing people being decapitated to be posted and shared on its site once again.
The social network had introduced a temporary ban in May following complaints that the clips could cause long-term psychological damage.
The US firm confirmed it now believed its users should be free to watch and condemn such videos. It added it was, however, considering adding warnings.
One suicide prevention charity criticised the move.
"It only takes seconds of exposure to such graphic material to leave a permanent trace - particularly in a young person's mind," said Dr Arthur Cassidy, a former psychologist who runs a branch of the Yellow Ribbon Program in Northern Ireland.
"The more graphic and colourful the material is, the more psychologically destructive it becomes."
Facebook allows anyone aged 13 and above to be a member.
Its terms and conditions now state that it will remove photos or videos that "glorify violence" in addition to other banned material, including a woman's "fully exposed breast".
New rules
The BBC was alerted to Facebook's change in policy by a reader who said the firm was refusing to remove a page showing a clip of a masked man killing a woman, which is believed to have been filmed in Mexico It was posted last week under the title, Challenge: Anybody can watch this video?
"Remove this video too many young innocent minds out there shouldn't see this!!!" wrote one user in the comments section below.
"This is absolutely horrible, distasteful and needs to be removed... there are too many young minds that can see this. I'm 23 and I'm very disturbed after seeing a couple of seconds of it," wrote another.
The social network later confirmed it was allowing such material to be posted again.
"Facebook has long been a place where people turn to share their experiences, particularly when they're connected to controversial events on the ground, such as human rights abuses, acts of terrorism and other violent events," said a spokeswoman.
"People are sharing this video on Facebook to condemn it. If the video were being celebrated, or the actions in it encouraged, our approach would be different.
"However, since some people object to graphic video of this nature, we are working to give people additional control over the content they see. This may include warning them in advance that the image they are about to see contains graphic content."
Facebook originally pulled decapitation videos after the Family Online Safety Institute - a member of its Safety Advisory Board - complained that they "crossed a line" bearing in mind how young some of its members were.