Doctors at a Birmingham hospital say a 13-month-old boy has less than 48 hours to live unless a suitable organ donor can be found for him.
Ethan Carroll, who is fighting for his life at Birmingham Children's Hospital, has already undergone 12 operations, including eight major procedures, since he was born.
He developed short gut syndrome at eight weeks old after an operation at a London hospital to remove a blockage in his gut resulted in his small bowel being removed.
Ethan now has to be fed intravenously through a tube in his neck which allows liquid to go directly into his blood stream.
His mother Keelin Carroll of Surbiton, Surrey, said she hoped bringing Ethan to the Children's Hospital - a centre of excellence for liver and small bowel transplants - would help to raise the profile of her son's plight.
The 27-year-old is keeping a bedside vigil with her partner Matthew Barnes. She said hearing about the case of liver transplant patient Harriet Stobbs, from Leicestershire, prompted her to seek the hospital's help.
After Harriet's parents made an emotional appeal in January, the Organ Donor Register received an extra 700 calls in just two days.
Despite having a transplant on January 28, the 14-monthold's condition worsened and she died on March 3.
But Ms Carroll said she hoped a suitable donor could be found for Ethan.
She said: "We've known for a while that one day he might need a transplant, and now that day is here.
"We heard about how baby Harriet was treated here and, as it has such a good reputation, we asked to bring him here.
"Ethan is a fighter, really he should be in intensive care, but doctors have given him until Wednesday if he doesn't get a transplant.
"I am just hoping a liver and small bowel donor can be found. I realise that means a family has to go through a tragedy, but hopefully they will see some good can come out of their loss." The family arrived at the Children's Hospital last Friday.
Dr Girish Gupta, a consultant paediatric liver specialist, said Ethan's condition was extremely rare.
He said: "Five or six children per million of the population have short bowel syndrome, and of those 20 to 40 per cent will develop complications that lead to liver disease. Ethan is very unwell and he is likely to die in the next few days if he does not get the lifesaving transplant he needs. For him, the organs need to come from a small child.
"We always hope that a donor can be found, it's whether they can be found in time."
Last year the hospital successfully completed 500 liver transplants, and 11 small bowel transplants.
Although 771 people donated organs in 2003/04, more than 440 people died awaiting a transplant because there was no suitable organ available.
A hospital spokesman said: "Ethan's story highlights the importance of carrying a donor card and how vital it is people discuss this decision with their families. If relatives don't know about their intention it can mean someone else misses out on a chance of life."
Anyone who wants to help can contact the NHS Organ Donor Register on 0845 60 60 400 or log onto the website www.uktransplant.org.uk, but must not call the hospital.