The European Union must put tougher measures in place to stamp out the growing problem of trading in counterfeit medicines, a report warns.
Pharmaceutical counterfeiting is on the increase
Professor David Taylor, of the University of London School of Pharmacy, said the problem had been concentrated in the developing world.
But the global nature of the drugs industry meant patients everywhere were now potentially at risk.
The UK regulator said a vigorous system of checks was already in place.
Some counterfeit medicines have been found to contain toxic substances, such as anti-freeze. Some have small amounts of the active substance, others none at all.
Professor Taylor, whose report is launched on Wednesday at the House of Commons, said increased rationing of drugs could play into the counterfeiters' hands.
He said: "Compared to the harm done by medicines counterfeiting in Africa and Asia, Europe is relatively safe.
"But there are growing risks, which will get worse if - for example - people believe that they cannot get new medicines that may benefit them for conditions such as cancer, dementia or influenza from publicly funded services."
World Health Organization statistics indicate 30% of medicines supplied in developing countries are fake.
In East European countries like Russia the proportion is 10%, while in wealthier areas like the UK it less than 1%.
Many of these have been purchased via the internet, but the Medicines and Healthcare Products Regulatory Agency (MHRA) is currently investigating three cases of fake treatments being supplied via the legal NHS medicines supply chain.
Professor Taylor's report calls for stronger legal penalties for medicine counterfeiting, and better controls over internet pharmacies, and entrepreneurs who trade in medicines.
He said the present system encouraged traders to buy medicines in countries where they are relatively cheap, and sell them on elsewhere at a profit.
While this was not illegal in itself, the fact that it was very difficult to monitor made it potentially attractive to counterfeiters.
The report, which was funded by a grant from the drugs firm Pfizer, also backs:
Shortening the medicine supply chains between pharmaceutical manufacturers and pharmacies
The introduction of 'track and trace' technologies that could allow product movements within Europe to be followed more closely by regulatory agencies
Matthew Worrall, of the Association of the British Pharmaceutical Industry, welcomed the report.
He said: "Pharmaceutical companies work actively with the police, the medicines regulator and customs officials to combat counterfeiting and, through measures like tamperproof packaging and holograms, are working to make the crime more difficult to attempt.
"Patient safety is of the utmost importance and, while the strength of UK supply chain means the risk of encountering counterfeit medicines here is low, we must remain vigilant and crack down on this crime."
Richard Freudenberg, Secretary-General of trade body BAEPD (the British Association of European Pharmaceutical Distributors) said: "¿Firstly it is worth noting that the report clearly states that ethical parallel importers should not be blamed for the criminal actions of counterfeiters.
¿Parallel trade in pharmaceuticals is a legal, legitimate and highly regulated business, which delivers significant cost savings to the NHS. The import and sale of counterfeit drugs is an entirely separate and illegal activity.
¿There has never been a case of counterfeit medicines reaching UK patients through parallel distribution, despite the efforts of big pharma lobbyists to suggest such a link exists."
In a statement, the MHRA echoed the view that the legitimate UK pharmaceutical supply chain was tightly regulated, and had one of the best international records for being difficult to breach.
In addition, the MHRA said it operated a comprehensive anti-counterfeiting strategy, which included Europe's largest medicines surveillance scheme to spot-check medicines on the UK market.
MHRA inspectors had also stepped up the number of checks for counterfeits they carried out when inspecting pharmaceutical manufacturers and distributors.
However, it went on: "It is recognised that no supply chain is impenetrable - whatever the regulatory and surveillance safeguards that may be in place."