Pharmacists are calling for better regulation of products claiming to contain cannabis derivative CBD.
There has been a spike in demand within the last twelve months, according to manufacturers.
Non-medicinal CBD is now on sale in High Street shops across the country, including chemists.
But the National Pharmacy Association says the products need clearer information and better checks on content.
CBD - cannabidiol - isn't marketed as medicinal cannabis. It doesn't have a psychoactive element that makes the user high.
Some studies indicate it can help with childhood epilepsy seizures, and other people think it helps them too.
Cannabidiol oil is being added to a range of products - from water, to chocolate, to make-up, tea and coffee.
Manufacturers claim sales in the UK are as much as £300m at the moment.
It's illegal to print any health claims on the products, but it's a grey area as to who checks the ingredients, or the amount of CBD oil actually contained in each product, many of which can be very expensive.
Jasmine Shah from the National Pharmacy Association, which represents hundreds of independent pharmacies, says an increasing number of pharmacists are stocking CBD products, despite the fact that she says "at the moment there is very limited research on the safety and efficacy of these products".
She says pharmacists would like "clear authoritative guidance which makes it easy for healthcare professions, consumers and patients to make informed choices".
CBD is classed as a food supplement, so it's governed by the Food Standards Agency.
Because it's a brand-new type of food there's a grace period, where it's allowed to be sold in stores, but the FSA has now asked manufacturers to give specific information about the product.
Manufacturers will have to include important scientific details like what it contains, purity levels, manufacturing practices, as well as providing detailed information to demonstrate it is safe for people to consume.
The FSA says that despite ample time and repeated requests to CBD manufacturers they've not heard enough from any company in this multimillion pound industry to give them authorisation yet.
That leaves those selling the product in a difficult position. Ms Shah doesn't think that selling CBD in pharmacies gives the products extra legitimacy.
She says "It's for each pharmacist to decide whether its suitable to stock a CBD product or not, but in terms of the safety and efficacy of it more research is required."
The Association for the Cannabinoid Industry is a new group representing around 20 CBD brands.
It says members are "unequivocally committed to achieving Novel Foods status via the Food Standards Agency".
But the FSA appears to be losing patience with the industry and said it expects "companies to comply with the novel foods process, which includes submitting safety information about their products".
"The FSA is considering the best way to ensure CBD food-related products currently on the market move towards compliance," it added.
In the meantime, customers buying any CBD product have no guarantees if the product is safe, or indeed if it contains any CBD oil at all.