Tests on more than 60 CBD products found the majority contained illegal substances, a council has found.
Kent Scientific Services (KSS), a laboratory run by Kent County Council, has been carrying out testing on behalf of several local authorities.
It found 44 out of 61 samples (72%) contained one or more of the psychoactive elements of cannabis.
KSS head Mark Rolfe said: “The issue with this is that people don’t know what they are consuming.”
One product was tested after a member of the public consumed it and then failed a workplace drugs test, having “never touched drugs in his life”.
“It was found to contain the drug for which he failed the test”, Mr Rolfe said.
Meanwhile, several samples contained “significantly less” CBD than claimed on the pack, while another two products did not claim to contain CBD but its presence was found.
Unlike other compounds found in cannabis, such as THC, CBD is legal.
It is classed as a novel food and is currently being assessed for safety by the Food Standards Agency (FSA).
The FSA has allowed about 6,000 CBD products to be marketed in the UK, pending final approval.
Linden Jack, deputy director of the FSA, said: “This survey highlights the importance of the work we are doing to bring this growing industry into compliance.
“We have asked to see the complete set of sampling results so we can work with local authorities to ensure that those CBD products that should not be on sale are removed from shelves.”
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