A study has found that over 80% of on-line advertisements for Internet pharmacies accepted by the search engine Yahoo were in violation of US federal and state laws.

The researchers were able to buy prescription drugs without a prescription from Yahoo Internet pharmacy advertisements, and in one case the drugs were imported from India, which is prohibited by US law, says the survey, which was conducted by research firms LegitScript.com and KnujOn.com.

Moreover, the researchers acquired prescription drugs without a prescription from an Internet pharmacy approved by PharmacyChecker – the service by which Yahoo, Google and Microsoft require their Internet pharmacy advertisers to be verified as legitimate - and listed on PharmacyChecker.com. Those drugs were also imported from India.

Yahoo's policy requires Internet pharmacy advertisers to be "based in" the USA or Canada. The report reviewed three Internet pharmacies that were approved as advertisers based on having a Canadian pharmacy license but, in all three cases, the pharmacies indicated that the drugs would actually be shipped from locations including India, Singapore or Barbados, and not Canada. Moreover, one advertiser approved as a licensed Canadian Internet pharmacy said it could fill prescriptions anywhere in the world except for Canada, because prescription drug importation is illegal there, the researchers report.

Earlier this month, an investigation by KnujOn and LegitScript into Microsoft's sponsored search results for Internet pharmacies displayed on its search engine Bing found that 89.7% of the ads reviewed were fake or illegal Internet pharmacies. The researchers had also been able to purchase prescription drugs without a prescription and had been sent counterfeit medications from bing.com on-line pharmacy advertisers. Following the publication of these findings, Microsoft responded, stating that it took the claims “very seriously.”

“Upon learning of the report, our internal editorial teams took immediate action to manually review all pharmacy-related keywords and remove any policy violators. Microsoft’s policies clearly require online pharmacies who advertise on Bing to adhere to US laws,” said the firm. However, shortly afterwards KnujOn made a further purchase of Meda Pharmaceuticals’ prescription muscle relaxant Soma (carisoprodol) - a controlled substance in some US states - from a bing.com advertiser without a valid prescription. The researcher was able to submit an order and received the drug without ever having visited a doctor or receiving a valid prescription, said the firm.

Moreover, this ad was not new. “We told Microsoft that this website was selling addictive medications without requiring a valid prescription in February,” said LegitScript’s president. John Horton. “We got no response, and the website has continued to advertise since then uninterrupted.”

Discussing the latest findings involving Yahoo, KnujOn president Garth Bruen said the firms were making this a public issue “because it's time for this to stop. If the search engines continue to knowingly facilitate illegal prescription drug sales, then we'll continue to issue these reports. Our reports stop when the problem is fixed,” he said.

“Yahoo needs to require that its Internet pharmacy ads adhere to US laws and National Association of Boards of Pharmacy standards,” added Mr Horton. “These are the same safeguards that govern brick-and-mortar pharmacies used throughout the US everyday. Shouldn't American Internet users be assured of the same safeguards online?”