Lucille McLauchlan was being treated in Ninewells Hospital in Dundee after she collapsed in her home in Broughty Ferry on Sunday.
Her children could not rouse her and she was taken to hospital by ambulance.
She was put on a life support machine but died this morning with her family around her, Ms McLauchlan's solicitor William Boyle said.
The 47-year-old was sentenced to eight years and 500 lashes in 1996 for her part in the murder of Yvonne Gilford.
She was pardoned 17 months later and allowed back to the UK.
Her co-accused Deborah Parry, who had been sentenced to death, was also released.
Mr Boyle said: "Lucille passed away in the early hours of this morning following a traumatic brain haemorrhage.
"Her life support system was switched off on medical advice and arrangements were made, along with Lucille's wishes, for her organs to be donated.
"All the family are in a state of shock, and they ask that her and their privacy be respected."