Researchers have said that an ingredient in a scorpion's sting could be used to stop heart bypasses failing.
Margatoxin, from the venom of the Central American bark scorpion, proved effective in preventing a complication.
New blood cells can grow inside blood vessels, restricting blood flow and eventually causing a graft to fail.
Heart experts said the University of Leeds study was "promising".
A common complication of heart bypass is neointimal hyperplasia, which is the blood vessel's response to injury.
It triggers the growth of new cells, causing an obstruction on the inside of the vessel.
In the study, the researchers tested a range of compounds, and found the scorpion toxin was the most effective.
The Central American bark scorpions are native to Central and South America and are usually about 5cm to 8cm long.
The venom is not deadly to humans but has a painful sting, which causes swelling and tingling.
The toxin works by blocking a potassium ion channel called Kv1.3 pore in the cell membrane that opens and closes in response to electrical signals and assists the delivery of calcium ion, which takes messages between cells.
"This is a good example of a substance that is dangerous in its natural form - a scorpion sting, having potential medicinal benefits if used appropriately," the BBC quoted Professor Peter Weissberg, medical director at the British Heart Foundation, as saying.
The research has been published in the journal Cardiovascular Research.