A couple killed a three-year-old boy by forcing him to consume a "significant" amount of salt, a court has heard.
Christian died four days after collapsing at the Gays' home
Ian, 39, and Angela Gay, 40, from Halesowen, West Midlands, are charged with the manslaughter of Christian Blewitt and child cruelty.
They planned to adopt Christian, who died in 2002 after collapsing at their home in Bromsgrove, Worcs. High salt levels were found in his body.
They were convicted of manslaughter in 2005 but won a retrial on appeal.
William Davis QC, told Nottingham Crown Court that Christian had suffered a brain haemorrhage and died four days after his collapse in December 2002.
'Banged his head'
"Our case in a nutshell is that the two of them forced Christian to consume salt, probably as some kind of punishment.
"Also, that they manhandled him in a wholly inappropriate way for a three-year-old child.
Ian and Angela Gay have always denied poisoning Christian
"They shook him, or banged his head against a mattress, or something like that."
Mr Davis said that although the prosecution did not believe the Gays intended to kill or seriously harm Christian, any reasonable person in their position would have realised their actions would cause him harm.
Earlier, Mr Justice Pitchford, presiding, told the jury that this was the second time Mr and Mrs Gay had been tried in relation to Christian's death.
He said: "At the first trial the jury found Mr and Mrs Gay not guilty of murder, but guilty of manslaughter.
"Mr and Mrs Gay appealed against their convictions on the grounds of fresh evidence.
"The Court of Appeal allowed their appeal and ordered a retrial on the charges of manslaughter and cruelty, which is how we come to be here today."
The judge reminded the jury that this was a fresh trial, and they should not research the case themselves.