A young family has ended up in hospital after unwittingly eating a marijuana-laced brownie allegedly sold to them at a Woodlands cafe.

The family, including two children aged three and five, sought medical help after they began acting strangely and seeing things that weren’t there soon after eating part of the same brownie.

The City of Stirling has confirmed the incident and charged the owners of the Bada Bing cafe with two counts of selling unsuitable food.

Urine tests at the hospital allegedly confirmed the presence of tetrahydrocannabinol (THC) in the mother and her two children and later tests of another brownie bought around the same time from the cafe also detected marijuana.

THC is responsible for most of marijuana’s psychological effects.

The family’s medical notes, reportedly seen by the ABC which broke the story on radio this morning, say the little girl was "inexplicably scared and afraid" and that her heart was beating very fast.

Her younger brother was noted as being drowsy, nauseous and pale.

The mother also began to experience symptoms while at Perth Children’s Hospital, reportedly feeling tired, seeing things that were not there, and “exhibiting occasional jerky movements, and responding to unseen stimuli”, according to the ABC.

It is unknown how the marijuana came to be in the brownie or what the circumstances were around it being allegedly sold to the family.

Speaking on radio this morning, father Michael and mother Sharon said the incident in March was still affecting their children, Emily who was five at the time, and son Thomas, 3.

“Our kids, Emily refused to eat anything without at least being so careful about what’s in it for a long time, it has played on their minds and they still ask, even now,” Michael, who asked that the family’s surname not be published, said.

“We go to other cafes or different places or even cook and they ask ‘does this have marijuana in it’,” Sharon said.

The family reported the incident to police who it is believed have not laid charges.

On a whim, Michael said he returned to the cafe soon after the incident and bought another brownie.

“I was a little concerned, because these processes take time, that no-one was actually checking what was happening at the cafe,” he said.

“I just thought I’ll go and buy another brownie because that’s one way at least to get something from the cafe at around the time that it happened.

“So I went and bought a brownie on my way back from giving an interview with police and just took that home and put it straight in the freezer and then a week or so later the police came and took that away.

“I understand from feedback from police and the council that that has been tested and is positive for components of marijuana.”

The City of Stirling said its environmental health team had investigated the matter after receiving a complaint and as a result had started proceedings to prosecute the business owners.

“The City has brought two charges against Nathan Sharp, trading as Bada Bing Café, of having sold food that was unsuitable on 2 and 3 March 2019 contrary to Section 18(2) of the Food Act 2008,” it said in a written statement.

“Analysis of one brownie confirmed the presence of THC and other cannabinoids.”

“As this matter is not yet before the courts, the City is unable to go into detail. However, we can assure our residents and the community that we have done a thorough investigation.

“This appears to be an isolated incident and the City believes it has addressed the risk.”

The owners of the Bada Bing cafe declined a request for comment.

The matter will go before Perth Magistrates Court on July 19.