Tributes are pouring in following the death of the 19-year-old British man whose inspiring fight against cancer brought more than $5 million into a cancer charity.

Stephen Sutton, diagnosed with the terminal disease at age 15, succumbed to bowel cancer Wednesday, dying peacefully in a Birmingham hospital in his sleep, doctors said.

In April, he posted an update on his condition to Facebook that put him in the spotlight and inspired millions to follow his case.

"It's a final thumbs up from me," he posted, with a selfie taken in his hospital bed, smiling and giving a thumbs-up. "I've done well to blag things as well as I have up till now, but unfortunately I think this is just one hurdle too far."

Sutton had hoped to help raise around $15,000 for the Teenage Cancer Trust, but such was the impact of his Facebook item and his selfie -- shared around 120,000 times in just the first hour after its posting -- that more than $5 million was donated in just days.

Likes of his Facebook page reached nearly a million and his Twitter following grew to tens of thousands. He posted a "bucket list" of hoped-for accomplishments, including skydiving, playing drums in front of an audience, and getting himself tattooed.

British Prime Minister David Cameron, visiting Sutton in a Birmingham hospital earlier this month, praised the youngster's "incredible" efforts in helping others.

"I can hardly think of anyone I've met with such a zest for life, and such a belief that you can get things done, and who wanted to live every minute," Cameron said.

"He was absolutely inspiring."

The donation to the Teenage Cancer Trust on behalf of Sutton was the largest single donation ever received by the organization.

"We are humbled and hugely grateful for what Stephen achieved and continues to achieve for us," the trust said in a statement.

His mother, in an announcement of his passing, wrote "her heart is bursting with pride but breaking with pain for my courageous, selfless, inspirational son."

The "ongoing support and outpouring of love for Stephen will help greatly at this difficult time, in the same way as it helped Stephen throughout his journey," she wrote.