Winehouse, 27, was found dead at her London home on July 23 following years of alcohol and drug addiction.
The inquest, in London, was told she had drunk heavily after abstaining from alcohol for three weeks and was poisoned by alcohol.
The singer had 416 milligrammes of alcohol per 100 millilitres of blood. The legal drink-drive limit is 80mg.
Coroner Suzanne Greenway said: "She had consumed sufficient alcohol at 416mg per decilitre (of blood) and the unintended consequence of such potentially fatal levels was her sudden and unexpected death."
Her father Mitch Winehouse has said that his daughter made repeated attempts to quit alcohol but without any medical supervision.
Following her death, Winehouse's 2006 album "Back to Black" has become the Britain's highest-selling album of the 21st century. (AFP)
She rocketed to fame after winning five Grammy awards off the back of "Back
to Black" and famously sang about her refusal to seek treatment for her
addiction in her single "Rehab".
