Brandon Muir died in hospital on 16 March 2008
A toddler was seen with bruises on his face just a week before he died, a murder trial has heard.
A witness said it looked like someone had grabbed 23-month-old Brandon Muir by the cheeks.
She also claimed Robert Cunningham, who is accused of murdering Brandon in Dundee last March, smoked cannabis while the boy was in the next room.
Mr Cunningham, 23, denies murder. The boy's mother, Heather Boyd, also 23, denies culpable homicide.
Ms Boyd is accused of failing to get Brandon medical treatment after he was allegedly attacked by Mr Cunningham.
Brandon died in Ninewells Hospital on 16 March last year after becoming ill at his home in Balunie Crescent, Dundee.
Former care assistant Joanne Dunn told the High Court in Glasgow that she once saw Mr Cunningham throw the boy across a room "like a dolly".
Miss Dunn, 24, said it looked as if Ms Boyd and Mr Cunningham were "both on drugs" when she turned up at Ms Boyd's flat a week before Brandon died.
She added: "Their eyes were totally white. There was used tin foil under the seat."
Miss Dunn then said her partner and Mr Cunningham went to smoke cannabis in the kitchen.
Prosecutor James Wolffe QC asked: "Where was Brandon?"
She replied: "He was on the couch. He had been told not to move while the cannabis was being smoked in the kitchen."
Miss Dunn said that when she had arrived at Ms Boyd's home there was an atmosphere that "you could cut with a knife".
She went on: "Brandon had bruises on his face as if someone had grabbed him by the cheeks. I don't know if that was what it was, it could have been something different, but that was what it seemed like."
Miss Dunn also spoke about an earlier alleged assault by Mr Cunningham on Brandon.
She said: "I saw him slapping Brandon, having him by the arm and basically throwing him. He threw him like a dolly."
The trial continues.