Sources have told Sky News that there were "no suspicious circumstances" surrounding the singer's death.
A Metropolitan Police statement read: "A post-mortem was conducted at St Pancras Mortuary today (25 July). It did not establish a formal cause of death and we await the results of further toxicology tests.
"The results of these further tests are not expected before 2 to 4 weeks. An Inquest opened at St Pancras Coroner's Court this afternoon (25 July) and was adjourned until 26 October."
Winehouse was found dead at her Camden home on Saturday afternoon. She was 27.
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The 'Back To Black' singer's parents Mitch and Janis Winehouse visited Amy's home today and told her fans that "her whole life was devoted to her family and her friends and you guys as well".
Stars from across the world of pop have paid tribute to the singer, including U2, Katy Perry, Lady GaGa and recent collaborator Tony Bennett.
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Watch Amy Winehouse perform 'Back To Black' live and acoustic at SXSW below: