Vinegar may kill rather than cure victims of box jellyfish stings, Queensland researchers have found.
The remedy, used for decades to treat stings, causes up to 60 per cent more venom from the lethal jellyfish to be discharged into the victim.
The findings have prompted calls for the Australian Resuscitation Council (ARC) to revise their sting treatment guidelines.
Research co-author and venom expert Jamie Seymour says the research changed his mind about vinegar.
"I thought I'd be able to show the world why you use vinegar," the James Cook University associate professor told AAP.
"But what we found was that by using vinegar, what you're effectively doing is increasing the venom load in the victim."
Much of the venom "fired" by a box jellyfish doesn't go into a person's bloodstream.
But vinegar activated the venom that would not otherwise have affected the sting victim, James Cook University and Cairns Base Hospital researchers found.
Patients who had vinegar poured on their wounds also needed higher doses of painkillers.
Prof Seymour said CPR should instead be administered immediately to anyone stung by a box jellyfish, which can kill within five minutes.
There have been 64 deaths in Australia attributed to box jellyfish stings during the past 130 years.