This picture taken on March 14 shows a Chinese policeman walking across a pile of fake medicines seized in Beijing in recent months, which were later destroyed. The rapid growth of Internet commerce has led to an explosion of counterfeit drugs sold around the world. - 

A conference at the Chatham House think tank in London is addressing the growing problem of counterfeit medicines. The World Health Organization (WHO) estimates that fake drugs account for up to half of all the treatments sold in some developing countries, putting millions of lives at risk.

The WHO claims that knock-off medicine is now a $75 billion a year industry. The problem is not confined to poor countries; one-tenth of the drugs sold worldwide are believed to be fake, with some finding their way into the U.S. and Europe .

“This poses a real threat to human health," says Professor Martin McKee of the London School of Hygiene and Tropical Medicine. "You might be taking drugs that don’t cure the condition you have, and if it’s a life-threatening condition you might die. Or you might be taking drugs that are toxic and the ingredients that are in them may kill you. There’s also the problem of sub-standard drugs encouraging the emergence of antibiotic resistance ”

Professor McKee, who is taking part in today’s conference, argues that the boom in internet sales of medicines has fuelled the fake drug industry.

The anti-impotence remedy Viagra, when sold online, is believed to be the most counterfeited treatment.

But McKee also blames slack regulation and the globalization of the pharmaceutical business. He points out that long and complicated supply chains make it easier to get fake drugs into the system.