The troubled former sports star has battled drink and drug problems over the years and on Monday he enrolled in a treatment facility in Arizona in a bid to kick his addictions for good.
However, Gascoigne suffered a severe reaction to a detox program and was taken to a local hospital, where he was treated in the intensive care unit.
He remained in hospital on Sunday as fellow soccer player Gary Mabbutt, who played with Gascoigne at English club Tottenham Hotspur, gave an update on his condition.
Mabbutt told Sky Sports News: "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 (Sunday), they had spoken to Paul and he's recovering and hopefully soon he will be back into the clinic to continue his rehab."
A group of Gascoigne's famous friends, including DJ Chris Evans, newsman Piers Morgan, soccer ace Gary Lineker and ex-England cricketer Ronnie Irani, all clubbed together to pay for the rehab trip.