Mum planned to murder family - court

A mother put drugs into her husband's and son's food for four days as she prepared to kill them and then herself, an Australian court has been told.

The 45-year-old woman - who cannot be identified - made the decision to end their lives after her husband discovered she had gambled away $500,000 of the family's money, the Supreme Court in Brisbane heard on Friday.

The court was told the woman decided her family hated her because of her addiction, and that they would be better off if they were dead.

It heard she put small doses of crushed up sedatives into their food over four days in late April last year to prepare them for the planned murder-suicide that weekend.

The court was told she had planned on feeding her husband and 11-year-old son large doses of the drugs before overdosing herself.

However, she checked herself into a mental health facility before she could carry out the plan at the family home in Brisbane's north.

The court was told the woman had a long history of mental illness and suicide attempts, and that her emotional wellbeing had deteriorated significantly after her gambling problem was discovered.

She pleaded guilty on Friday to eight counts of supplying drugs with a circumstance of aggravation.

The woman was released immediately on three years' probation after having already served more than seven months behind bars.

Justice James Douglas ordered she receive psychiatric treatment.

- AAP