Venom from a small snail could be used to develop a treatment for chronic pain, scientists suggest according to BBC.
Normally used to paralyse or kill its prey, the venom also contains a compound that appears to act as long-lasting pain relief.
In research on rats, the compound was still working three days later.
The findings meant it may be possible to create a new pain therapy for patients who had run out of options, the researchers said.
Most medicines for moderate to severe pain, called opioids, work by reducing the perception of pain.