Synthetic cannabis can cause psychosis, aggression and liver damage and is not safe just because some shops sell it, police have warned after seizing about 57kg of the substance.
Police found the haul, with a street value of more than $800,000, after simultaneous raids on three southern suburbs businesses and two homes in August.
The raids were the result of Operation Gallows by Peel district crime team officers in July after tip-offs that illegal synthetic drugs were being distributed from shops, homes and carparks around Rockingham, Port Kennedy and Warnbro.
Det-Sen. Sgt Brett Ranford said relatives and friends of people who had taken the drugs had called police concerned about side effects they had witnessed, including psychosis and increased aggression.
Synthetic cannabis is created by spraying a chemical on to herbs or other plants. It is smoked to mimic the effects of cannabis.
But ChemCentre forensic chemistry manager Dominic Reynolds said some of the substances recently tested produced effects more similar to amphetamines.
Det-Sen. Sgt Ranford said police were worried, particularly ahead of school leavers' celebrations, that children would buy the product under the misconception that it was safe because it was sold from a shop or in a packet.
"But that is not true, they're taking a massive risk because they don't know what they're taking and these chemicals are even unknown to the people that are selling them," he said.
"Research is limited because the drug is new, but early indications are that it exacerbates underlying psychiatric problems and anecdotally we're seeing it as a factor in domestic assaults because it heightens people's aggression levels."
Police questioned a man and a woman after the raids on businesses in Port Kennedy and a Warnbro home netted more than 35kg of suspected synthetic cannabis and about $150,000 cash.
Another man was questioned over more than 20kg of the product found during raids on an unrelated Rockingham business and home.
The 57kg of drugs seized was being tested to identify the chemical compounds involved before charges could be laid.