Scientists at the University of Edinburgh have identified a protein which they hope could reduce liver damage in people who have overdosed on paracetamol.
The team found that overdose patients who suffer the greatest liver damage have higher levels of a protein known as cyclophilin A in their urine.
Researchers say treatments to block the harmful effects of the protein may aid such patients, reports the BBC.
Lead researcher Dr James Dear said: "Around 30 percent of patients who have developed significant liver injury following a paracetamol overdose die.
"If we can find a way to block the protein cyclophilin A, we would hope to limit further damage to the liver.
"Alternatively, measuring levels of the protein could indicate straight away which patients will need a liver transplant.
"Waiting a number of days means that valuable time is lost in trying to find a suitable match. Even gaining an extra day or two could save a life."
Dr Varuna Aluvihare, a consultant hepatologist at King's College Hospital, London, said a test to assess which patients needed a liver transplant would potentially be of great use.
The findings will be presented at a meeting of the British Pharmacological Society.