A woman died from complications arising from being wrongly prescribed too much vitamin D, an inquest has heard.
Eileen Cowles, 86, was prescribed colecalciferol to help her recover from surgery on a broken hip.
Wakefield Coroners' Court heard she was told to take daily what should have been a month's dosage.
A home office pathologist told the inquest it was unlike anything he had seen in 35 years.
Dr Richard Shepherd said Mrs Cowles died as a result of complications from hypercalcaemia, brought on by excess vitamin D, and a gastrointestinal haemorrhage.
He said: "I don't think I've ever come across hypercalcemia in this way before.
"Mrs Cowles was given excess colecalciferol that induced the high levels of calcium, which led to a number of complications.
"She died as a result of complications of excess colecalciferol."
He could find no natural explanation for Mrs Cowles's calcium levels during the autopsy, he said.
The inquest also heard both Mrs Cowles's care home in Guiseley and local pharmacist had raised concerns about the prescription with her GP before her death in April 2015.
But Dr Claire Wiles responded on both occasions by saying the prescription was correct, the court heard.
The inquest continues.