Consumers who go online to buy medicines run the risk of being ripped off or worse, a new report has found.

The Summer 2007 Brandjacker report from fraud advisor Markmonitor suggested that many popular brands of prescription drugs on sale at hugely discounted prices are either counterfeit, expired, stolen, diluted - or a different medicine to that stated.

As well as risking their health, people buying from these sites could have their credit card details stolen by cyber criminals; over half of sites analysed in the report did not use secure payment facilities. A fifth of post-purchase emails captured in the Markmonitor analysis also contained links to unencrypted customer data.

The problem is made worse by the fact there is currently no widespread use of a standard industry logo internationally or nationally, that could help consumers verify the credentials of an online pharmacy.

Of the 3,160 online pharmacies analysed in the report only four had Verified Internet Pharmacy Practice Sites accreditation. This was set up in 1999 by the National Association of Boards of Pharmacy (NABP) to assure consumers an online site is a legitimate pharmacy.

However, the UK is not a signatory to the NABP, which is a collaboration of three US states, eight Canadian provinces, two Australian states and South Africa.

The report also found one in 10 of the pharmacies clearly state that no prescription was required to purchase the medication which should raise alarm bells.

However, the Medicines and Healthcare products Regulatory Agency (MHRA), sounded a note of caution about the study. This Government watchdog oversees the quality and safety of medicines available in the UK and said “at first glance it was initially unhappy” with the report.

Sara Coakley, a representative for the MHRA, told Computeractive: “We didn't feel that the report made much sense as the figures didn't add up. Plus we're unsure of the methodology used.”

She said that the organisation would be looking into the report and questioning it further within the next few weeks. Until then Coakley recommended that people steered clear from buying medicines over the internet and continued to seek professional advice.

The Royal Pharmaceutical Society of Great Britain agreed with this and also advised consumers to verify that the website was operated from a registered retail pharmacy.

Earlier this year it ran an internet pharmacy logo which is designed to help the public identify if a website is linked to a bona fide, UK-registered pharmacy or not. The Society is currently organising a wider roll out of this logo.