Millions of UK surfers could be playing Russian roulette with their health by buying prescription-only medicines from rogue internet sites, according to new research.

To help minimise the dangers, the Royal Pharmaceutical Society of Great Britain (RPSGB) has launched the Internet Pharmacy Logo to help customers identify sites operated by bona fide UK pharmacies.

The research shows that over two million people across Britain regularly purchase medicines via the web.

While a number of legitimate pharmacies provide online services, there are a number of sites offering medicines with no professional qualifications or healthcare expertise.

In many cases, medicines purchased from such sites are counterfeit, substandard or unapproved, which can put public safety at risk.

The research also reveals that almost a third of people admit to not having a clue about online pharmacy regulations. All pharmacies across Britain, including those offering internet services, must be registered with the RPSGB.

The Internet Pharmacy Logo will be visible on the home page of participating online pharmacies, and features the unique RPSGB membership number of the pharmacy operating the site.

The logo will also link through to the RPSGB registration pages to allow visitors to check the legitimacy of a particular site, and the pharmacists running the practice, before making a purchase.

"The internet presents a real danger to people's health," said David Pruce, director of practice and quality improvement at the RPSGB.

"Dishonest traders are selling medicines online without any relevant professional qualifications or healthcare expertise. The products they sell can be poor quality at best and dangerous at worst.

"The public must be vigilant and we recommend that they use the presence of this logo in conjunction with routine checks when deciding whether or not it is safe to buy."

The routine checks include making sure that the site is connected to a 'bricks and mortar' pharmacy, and avoiding sites that offer to supply prescription-only medicines without a prescription.