Paul Gascoigne remains in hospital in the United States but there are no fears for his life, according to his long-time therapist.
The former England midfielder, 45, travelled to a clinic in Arizona earlier this week in a bid to tackle his alcohol addiction.
He suffered a bad reaction to the detox programme he was placed on at the clinic and his former Tottenham team-mate Gary Mabbutt told Sky Sports News that Gascoigne was moved to the intensive care unit of a local hospital.
Dr John McKeown, a psychotherapist who has worked with Gascoigne for more than 10 years, said in a statement: "Following reports today I feel it's appropriate to bring people up to date on Paul Gascoigne's condition.
"Paul has experienced severe complications with his detoxification. This is not unusual for someone who has been drinking as heavily as he has.
"Paul was transferred from the US Clinic Cottonwood to a local hospital to be monitored so as to be completely satisfied that there are no other complications to his health.
"He is still receiving that care but the hospital has reassured me that he is up and about walking. There are no fears for his life. We will aim to keep everyone concerned updated on a regular basis."
Gascoigne's management confirmed earlier this week that the former player had willingly been admitted to a treatment centre in the USA in another bid to conquer his addiction.
Former Spurs team-mate Mabbutt told Sky Sports News earlier on Sunday: "Unfortunately over the last few weeks Paul has had a relapse, which culminated finally, last Monday, in Paul asking for help.
"By Monday afternoon he was on a plane out to Arizona to a clinic specialising in dealing with Paul's specific problems. The first thing he underwent was a detox, unfortunately Paul had a very bad reaction to the detox and the clinic decided that as a precaution it was best to transfer him to hospital.
"He was transferred to hospital in intensive care where they could monitor him 24-7. But I spoke to Paul's medical team in the UK this morning, they had spoken to Paul and he's recovering and hopefully soon he will be back into the clinic to continue his rehab.
"Over the years he has had a lot of support from the football family, but of course it could be a long road to recovery. Now Paul's asked for the help we can focus on getting through this."
Gascoigne, who starred for England at the 1990 World Cup and is regarded as one of the most talented English players of all time, began his career at home town club Newcastle before moving on to Tottenham. He was signed by Italian side Lazio before enjoying spells with Rangers, Middlesbrough and Everton among others in the latter part of his career.
During his time at Everton he made a big impression on Wayne Rooney, who was then coming through the youth ranks at Goodison Park.
The England striker pondered whether Gascoigne would have benefited from working under Sir Alex Ferguson, having been close to a move to Manchester United before opting for Spurs.
"You never know what would have happened but I know Alex Ferguson is the best in looking after his players and making sure his players are doing the right thing," the United forward told Daily Star Sunday.
"I'm sure he would at least have tried to help him.
"It's a shame what's happening to Gazza. He was a hero of mine growing up. I'm sure everyone, every England fan and every Paul Gascoigne fan wishes him the best of luck. It's a sad time for him just now and I wish him all the best."
Gascoigne's former England team-mate Gary Lineker tweeted in the early hours: "Gazza is struggling, Let's hope he can hang on in there. Others have generously offered help. #GetwellGazza."
Gascoigne, who has spoken about alcoholism problems in the past, was sectioned five years ago under the Mental Health Act.