Amy Winehouse is suffering from the early stages of Emphysema and an irregular hearbeat, according to her father, Mitch.
Speaking to the Sunday Mirror, Mr Winehouse said his daughter would have to wear an oxygen mask if she didn't tackle her problem with drugs.
In its most common form, Emphysema is often caused by a long-term exposure to tobacco smoke and causes the lung tissue to lose its elasticity.
"The doctors have told her if she goes back to smoking drugs, it won't just ruin her voice, it will kill her," Mr Winehouse is quoted as telling the newspaper.
"There are nodules around the chest and dark marks. She has 70 percent lung capacity."
Winehouse was admitted into hospital last Monday (June 16th) after fainting whilst “doing admin” at her home in North London.
Mr Winehouse said that his daughter was still expected to make two public appearances this week, on Friday (June 27th) on behalf of Nelson Mandela and the following day at the Glastonbury Festival.
The doctors have said that medically there isn't any reason why she can't do Glastonbury," he said.
Amy Winehoue meets fans last Monday
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