A UK study shows that many strong painkillers are widely available on the internet and some experts warn against the dangers of drugs over the internet.

Researchers from Edinburgh University find that in UK, there are 35 such websites as selling some prescription-only painkillers without asking for a prescription.

According to the government officials, this online purchase of painkillers can prove very harmful.

The study has been published in the Journal of Clinical Pharmacology.

When surfing through Yahoo and Google search engines, the researchers noticed that there were nearly 100 selling drugs to consumers in the UK.

They found that nearly half of them were selling prescription-only drugs, however, 76 percent were not requiring customers to provide a prescription.

There were six companies which requiring a prescription, but they were accepting it via fax or email which according to the researchers can be modified or forged.

The drugs that were available online include tramadol (opioids) celecoxib and naproxen .These drugs are often prescribe for conditions like arthritis.

Professor David Webb, who authored the study, says in a news release at Edinburgh University that many of these drugs must not be taken without doctor advice, but you can get these drugs just with few clicks of the mouse.