George Best is "a little better" this morning but is still on a ventilator, his doctor told reporters.
Prof Roger Williams, who oversaw Best's liver transplant in 2002, said the 59-year-old had an unexplained bowel infection, which was causing complications to his treatment but stressed that he remained in a stable condition.
The former Northern Ireland star is in intensive care at the private Cromwell Hospital in London and is suffering from internal bleeding. He was admitted to the hospital nearly four weeks ago with an infection and his condition deteriorated when it spread.
Prof Williams said microbiologists had confirmed that the infection was not linked to MRSA and added: "I can't say how serious the infection is and the bleeding comes and goes. "I have looked after him for a long time and we are not giving up."
Best has a well-documented history of alcoholism and caused anger when he embarked on a drinking binge within months of the operation - despite vowing to stay dry.
He had been told one more drink could kill him when he underwent the surgery in July 2002 and was criticised by a liver specialist for putting people off organ donation.
Best's latest health problems are thought to be related to immuno-suppressant drugs he has been taking since his transplant to stop the organ being rejected.
PA