A verdict of misadventure was recorded into the 27-year-old’s death after an inquest heard she was more than five times the drink-drive limit.
St Pancras coroner Suzanne Greenway said the “unintended consequence” of Winehouse drinking so much alcohol was her “sudden and unexpected death”.
Three empty vodka bottles, two large and one small, were found at her flat, St Pancras Coroners Court heard.
The inquest heard the singer, who won five Grammy awards in 2008, had 416mg of alcohol per 100ml of blood. The legal drink-drive limit is 80mg.
The pathologist who conducted her post-mortem examination said 350mg of alcohol per 100ml of blood was considered a fatal level.
The examination found Winehouse’s vital organs had been in good health but she had huge amounts of alcohol in her system which could have stopped her breathing and sent her into a coma.
Toxicology tests showed there were no illegal substances in her system when she died.
The inquest was told she was found in her bed by live-in guard Andrew Morris, who looked in on her at 10:00 hours, but thought she was asleep.
Five hours later she was “lying on the bed in the same position”, he said.
“I was immediately concerned, went over and checked to see if she was OK,” he added.
“I checked on her and realised she wasn’t breathing and had no pulse, so called the emergency services.”
Winehouse had kicked her drug habit but fell back into a pattern of abstaining from drink for weeks then starting again for a few, the inquest heard.
The coroner was told Winehouse had not had a drink in the three weeks to 22 July.
Her GP, Dr Christina Romete, who had been treating the star for several years, said the night before her death, the singer told her she did not know if she was going to stop drinking but “she did not want to die”.
“She was looking forward to the future,” the doctor said.
Winehouse was taking medication to cope with alcohol withdrawal and anxiety and was reviewed last year by a psychologist and psychiatrist about her drinking.
“She had her own way and was very determined to do everything her own way,” said Dr Romete.
“Including any form of therapy. She had very strict views.”
After the inquest, Winehouse’s family issued a statement thanking people for their messages of support.
They said it was “some relief to finally find out what happened to Amy”.
Their statement added: “We understand there was alcohol in her system when she passed away – it is likely a build-up of alcohol in her system over a number of days.
“The court heard that Amy was battling hard to conquer her problems with alcohol and it is a source of great pain to us that she could not win in time.”
Since her death, Winehouse’s 2006 album Back to Black has become the UK’s bestselling album of the 21st Century.