Scientists have developed a new pain-relief pill from a chemical in sea snails' saliva that they use to catch their prey.

It was found to be as effective as morphine for relieving the most severe forms of pain but without the added risk of addiction.

Marine cone snails produce saliva that contains a deadly dose of peptide toxins to help the slow-moving creatures catch prey.

They inject passing victims with needle-like teeth that shoot out of their mouths, the Daily Mail reports.

Scientists have already transformed one of the chemicals into a pain-reliever for humans. However, it has to be injected directly into the spinal cord which limits how much of it can be used.

Now researchers in Australia, led by David Craik of the University of Queensland, have developed a form of the painkiller that can be taken orally.

The modified chemical was found to reduce severe pain in rats at a much lower dose than existing medications, according to an article in Chemical & Engineering News.

'For years people have been saying that peptides make fantastic drug leads because they're very potent,' Craik told the magazine.

However, peptides were regarded as poor drugs as they were not stable and could not be taken orally.

This could be set to change after the team led by Craik found they could stabilise the amino-acid chains by synthetically lashing the head to the tail.

'All you need is for the ends to be roughly close to one another,' he said.

The drug could potentially revolutionise the treatment of the most severe forms of pain and Craik is keen to take his research further.

'The most challenging aspect has been just raising the money to get it commercialised,' he told Chemical & Engineering News.