Coroner Suzanne Greenaway gave a verdict of "death by misadventure," saying the singer died of accidental alcohol poisoning when she resumed drinking after weeks of abstinence.
"The unintended consequence of such potentially fatal levels (of alcohol) was her sudden and unexpected death," Greenaway said.
The singer, who had fought a very public battle with drug and alcohol problems for years, was found dead in bed at her London home on July 23 at age 27. An initial autopsy proved inconclusive, although it found no traces of illegal drugs in her system or signs of injury.
Pathologist Suhail Baithun told the inquest into the singer's death that blood and urine samples indicated that Winehouse had consumed a "very large quantity of alcohol" prior to her death. The level of alcohol in her blood was 416 milligrams per 100 milliliters, he said - a blood alcohol level of 0.4 percent.
The British and U.S. legal drunk-driving limit is 0.08 percent.
Such levels of alcohol intake could have stopped her breathing and sent her into a coma, Baithun added.
Police Detective Inspector Les Newman, who was called after a security guard found Winehouse, said three empty vodka bottles - two large and one small - were found in her bedroom.
Winehouse's doctor, Dr. Christina Romete, said the singer had resumed drinking in the days before her death. Prior to that, Winehouse had stayed away from drink for most of July, she said, although she had been swerving between abstinence and heavy alcohol use for a long time.
"She's made tremendous efforts over the years," Romete said, adding that alcohol became Winehouse's main problem after the singer gave up illicit drugs in 2008.
Romete, who saw Winehouse the night before she died, described the singer as "tipsy" but calm. She said Winehouse had not spoken of suicide, and had talked about her upcoming birthday.
The doctor said Winehouse had been prescribed drugs including the sedative Librium to help her cope with the symptoms of alcohol withdrawal, but the coroner said these had played no role in her death.
Winehouse was last seen by her live-in security guard, Andrew Morris, who said he had heard her laughing and listening to music the night before she died.
He said he knew she had resumed drinking, but did not notice anything unusual until he found that she had stopped breathing in bed the next afternoon.
"She did it moderately... she wasn't drinking to get drunk," Morris told the coroner's court.
Doctors say acute alcohol poisoning is usually the result of binge drinking - the human body can only process about one unit of alcohol, or about half a glass of wine, an hour. Having too much alcohol in the body can cause severe dehydration, hypothermia, seizures, breathing problems, and a heart attack, among other difficulties.
There is no minimum dose for acute alcohol poisoning and the condition varies depending on a person's age, sex, weight, how fast the alcohol is drunk and other factors such as drug use.
Dr. Joseph Feldman, chief of emergency services at Hackensack University Medical Center, New Jersey, said that Winehouse likely developed tolerance to larger quantities of alcohol than one would expect after drinking heavily for years. He also said that the sedative Winehouse was on, Librium, wouldn't have stopped someone from having seizures if they were in alcohol withdrawal.
"It's easier to withdraw from heroin than it is from alcohol ... withdrawal (from alcohol) can cause anxiety, tremors, hallucinations, the sensation of things crawling all over you," he said.
He said those symptoms sometimes push people back to alcohol, which can result in poisoning.
"It's possible she could have been saved if she had been found (or treated) earlier," he said. "A lot of treatment is supportive care, like IV fluids and making sure they don't vomit."
The singer's parents attended the hearing, but did not speak to reporters. In a statement, Winehouse family spokesman Chris Goodman said it was a relief to the family "to finally find out what happened to Amy."
"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," he said.
Winehouse's breakthrough "Back to Black" album, released in 2006, was recently certified as the best-selling disc in Britain so far during the 21st century. The updated take on old-time soul also earned five Grammy Awards.
Although the singer was adored by fans worldwide for her unique voice and style, praise for her singing was often eclipsed by lurid headlines about her destructive relationships and erratic behavior. In June, the singer abruptly canceled her European comeback tour after she swayed and slurred her way through barely recognizable songs in her first show in the Serbian capital, Belgrade. She was booed and jeered off stage and had to return to Britain to recover.
Her last public appearance came three days before her death, when she briefly joined her goddaughter, singer Dionne Bromfield, on stage at The Roundhouse in Camden, near her home.
Associated Press Medical Writer Maria Cheng contributed to this report.