Scientists have created powerful painkillers from the venom of snails, it has been revealed.
The substances, based on a tiny protein found in cone snails' venom, could be more effective than morphine.
They may one day lead to the development of a drug to treat severe and chronic nerve pain.
Prof David Craik, from the University of Queensland in Australia, described the development of five new 'experimental' painkillers as an 'important incremental step'.
"This could serve as the blueprint for the development of a whole new class of drugs capable of relieving one of the most severe forms of chronic pain that is currently very difficult to treat," he said.
Cone snails, which are typically found in warm and tropical seas, use venom to paralyse their prey.
The fluid contains hundreds of small proteins, known as conotoxins, which appear to have an analgesic effect in humans, said Prof Craik.
Researchers are working on the development of a conotoxin-based drug that can be taken orally - unlike the only drug that uses the protein now, which must be injected into a patient's spine.
And preliminary trials are promising - with a prototype drug tested on rats shown to 'significantly reduce pain'.
"We don't know about side effects yet as it hasn't been tested in humans, but we think it would be safe," said Prof Craik, who will soon present his discovery at an American Chemical Society conference.
“It acts by a completely different mechanism than morphine, so we think it has a minimal possibility of producing the side-effects of that medication. That is one of the big advantages of this drug."