Facebook is allowing people to post online videos showing graphic violence including decapitation, reversing a temporary ban which was introduced earlier this year.
The social network said its rules allow people to share such material to condemn it, but not to glorify it, the BBC reports.
It also said it was considering adding warnings about such images.
Facebook allows anyone aged 13 and above to be a member.
The network's 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".
"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 spokesperson.
She says the video is being shared on Facebook to condemn it.
"If the video were being celebrated, or the actions in it encouraged, our approach would be different."