Instagram will not allow any graphic images of self-harm on its platform following pressure from parents of suicide victims.
The move comes after a demand that social media companies "purge" their platforms of content that promotes self-harm and suicide, made by the family of 14-year-old Molly Russell.
Molly's family discovered she had been viewing graphic images of self-harm on the platform before taking her own life.
Head of Instagram Adam Mosseri said in a blog post on Thursday that "nothing is more important to us than the safety of people in our community".
He wrote: "Over the past month we have seen that we are not where we need to be on self-harm and suicide, and that we need to do more to keep the most vulnerable people who use Instagram safe."
After a comprehensive review with global experts and academics on youth, mental health and suicide prevention, the company has decided to clamp down on graphic images of self-harm.
Mr Mosseri continued: "We will not allow any graphic images of self-harm, such as cutting on Instagram - even if it would previously have been allowed as admission.
"We have never allowed posts that promote or encourage suicide or self harm, and will continue to remove it when reported.
"We will not show non-graphic, self-harm related content - such as healed scars - in search, hashtags and the explore tab, and we won't be recommending it."
However Mr Mosseri added that Instagram will not be removing this type of content "entirely" as it wants to support people who need help.
The blog post added: "We don't want to stigmatise or isolate people who may be in distress and posting self-harm related content as a cry for help.
"We want to support people in their time of need - so we are also focused on getting more resources to people posting and searching for self-harm related content and directing them to organisations that can help."
Instagram said its aim is to eventually remove all self-harm and suicide imagery from hashtags, search the explore tab or as recommended content.
Instagram's bosses met Health Secretary Matt Hancock on Thursday afternoon to discuss content on suicide and self-harm.
After the meeting, Mr Hancock said: "This is an important change, there's lots more things that we need to see, like transparency over how much damaging material there is and also I want to see when people search for material about suicide and self-harm, that they are directed better to help, to the Samaritans, to the NSPCC.
"We've seen progress, the discussions were productive, and the willingness to try and solve this problem.
"What all the companies that I met today committed to was that they want to solve this problem, and they want to work with us about it."
He added that "what really matters is when children are on these sites they are safe" and there is a lot more work to do.
In a statement, Molly Russell's father Ian said he welcomed the changes made by Instagram.
He said the decision "is encouraging to see that decisive steps are now being taken to try to protect children from disturbing content on Instagram and I hope that the company acts swiftly to implement these plans and make good on their commitments."
Mr Russell added: "It is now time for other social media platforms to take action to recognise the responsibility they too have to their users if the internet is to become a safe place for young and vulnerable people."
On Tuesday, it was announced that social media firms are facing new laws requiring them to protect users by the end of the year.
Parents of suicide victims have also put pressure on social media platforms to make changes.
Sky News previously spoke to the father of Zoe Watts, who took her own life aged 19 in March 2017.
Her father Keith blamed failings in the health service, but also said messages and images his daughter accessed on social media were a contributing factor.
He said: "I've seen some of the images of young girls with some pretty bad slashes on their arms and there's kind of a bit of a brag about it.
"Zoe printed off images of emaciated girls. The one message that rings in my mind was message saying that 'your grumbling stomach is actually an applaud for not eating'."