A man poisoned by his wife was seen lying on a hospital floor pretending to drive a bus, a court heard.
John Mook was taken to York Hospital after ingesting the anti-depressant drug amitriptyline in January.
A toxicology expert told York Crown Court an overdose of amitriptyline could prove fatal.
Heather Mook, 57, of Heslington Road, York, denies administering a poison or noxious substance to endanger life but has admitted administering rat killer.
In total she has admitted five less serious alternative charges, including a number of theft-related offences.
Mrs Mook admits administering the drugs but denies intending to put his life at risk.
Her daughter, Tracy Hardwick, told the jury she had never seen Mr Mook "looking so ill" and was "totally shocked" when she visited him in hospital.
"He was lying on a mattress on the floor staring at me pretending he was fishing and driving a bus," she said.
"Nurses said they didn't know what was wrong with him. Every test they performed on him came back negative."
Tests eventually showed an overdose of anti-depressants.
The court was told Mrs Mook poisoned her husband in an attempt to confuse him while she stole £43,000 from his elderly mother.
She tried to cover up her thefts by giving her husband the anti-depressant drug, the jury heard.
She also gave her husband rat killer pellets on one occasion.
Mr Mook, a 60-year-old bus driver, was left confused, tired and agitated by the poisoning.
Toxicology expert Professor Robert Forrest said an overdose of amitriptyline could prove fatal, and symptoms include confusion and tiredness.
He told the jury it was possible for someone to have a fit and for their heart to stop.
"There is no guarantee the patient will leave hospital alive," he said.
The trial continues.