Pharmacists are refusing to stock a chemical used to sterilise babies' bottles and in gardening because they are worried it will be used by drug addicts.
A number of chemists in Brighton and Hove are no longer stocking citric acid because it can be used by heroin users to make their drug easier to inject.
Mother Kelly Davis was told by staff at Boots in George Street, Hove, that they no longer stocked the product because drug users were going into the store.
Pharmacists also said they were wary about customers asking for acetone because drug users were known to use the industrial solvent to clear cocaine from crack pipes.
One chemist told The Argus that even an excessive amount of paracetamol is monitored.
Any individual coming into a pharmacy to buy paracetamol three times in one week would arouse suspicion and employees would be likely to refuse service and suggest that the person seek medical help.
Miss Davis, 28, from Hove, said: "I had seen on the Internet that citric acid was recommended for sterilising babies' bottles so I went to Boots to get some. I was shocked when they told me that they no longer stocked it because it was used by drug addicts."
Mike Pattinson, director of operations for the charity CRI, said: "Heroin has to be dissolved to be injected. There is so much rubbish in most batches of heroin that it does not dissolve so users use citric acid to break it down to liquid form. If they can't get hold of citric acid, they will use vinegar or lemon juice which is much more dangerous.
"Citric acid is available for free at needle exchanges and we would recommend users to get it from here so they can also get access to professional drug help."
A Boots UK spokesman said: "Citric acid is a chemical which can unfortunately be misused in a number of ways, therefore we believe that recognised chemical suppliers are better placed to supply these products to customers.
"This is also to ensure that they are being supplied in appropriately packaged and labelled containers with the relevant safety advice."
Kevin Shepherd, the Lloyds Pharmacy area manager for Brighton, said: "We do stock citric acid within the dispensary and pharmacy teams are able to sell this product."
"As with all products we sell within our pharmacies, questions are asked to the customer to ensure that it is being sold for an appropriate use and is always sold at the pharmacist's discretion."