The incipit of a brief item in the Telegraph:
The Queen of the Nile ended her life in 30BC and it has always been held that it was the bite of an asp – now called the Egyptian cobra – which caused her demise.
Now Christoph Schaefer, German historian and professor at the University of Trier, is presenting evidence that aims to prove drugs and not the reptile were the cause of death.
“Queen Cleopatra was famous for her beauty and was unlikely to have subjected herself to a long and disfiguring death,” he said.
He journeyed with other experts to Alexandria, Egypt, where they consulted ancient medical texts and snake experts.
“Cleopatra wanted to remain beautiful in her death to maintain her myth,” he says on the Adventure Science show screened by the German television channel ZDF.
“She probably took a cocktail of opium, hemlock and aconitum. Back then this was a well-known mixture that led to a painless death within just a few hours whereas the snake death could have taken days and been agonising.” [...]
Hopefully we’ll hear more about this … back in 2004 there was an item in the Times in which a forensic expert suggested it would have likely taken two hours for Cleopatra to die by the bite of an asp:
… and a year later there was an item in Acta Theologica Supplementum 7 (not sure who the author is; the link is a pdf) on the subject which also suggested aconite as a possibility.