Apparently there were no drugs in her system:

LONDON – Amy Winehouse had no illegal drugs in her system when she died, and it is still unclear what killed the singer, her family said Tuesday.

    A toxicology report shows that some alcohol, but no illegal drugs were found in Amy Winehouse's body. The singer died July 23.

    By Matt Dunham, AP

A toxicology report shows that some alcohol, but no illegal drugs were found in Amy Winehouse's body. The singer died July 23.

The family said in a statement that toxicology tests showed "alcohol was present," but it hasn't yet been determined if it contributed to her death.

The 27-year-old soul diva, who had battled drug and alcohol addiction for years, was found dead in her London home on July 23, and an initial post-mortem failed to determine the cause of death.