Redback spider antivenom doesn't work and people are better off taking over-the-counter paracetamol, a Newcastle study has found.
In the trial, 224 Australian patients were treated for redback spider bites with either standard pain relief or antivenom.
At the end of the three-year study at Newcastle's Calvary Mater Hospital, clinical toxicologist Dr Geoff Isbister concluded that antivenom did not work.
"We found there was no difference between the people who got the antivenom and the people that didn't," Isbister told ABC Radio.
The results confirmed a suspicion within scientific circles that the antivenom simply didn't work, he said.
"Ultimately, we'll start to change practice, or at least make people question what exactly they're doing when they treat redback spider bites."
Antivenom also has its risks. Produced using horse protein, it can cause an allergic reaction in one in 20 people.
"This is an example of something that works in a test tube, but doesn't translate into making patients better," Isbister said.
Unlike funnel-web spiders, redback bites are not fatal to humans, but can cause pain and nausea.
Simple pain relief and anti-inflammatory medication are enough to treat the symptoms of a redback bite.
The study was presented at an international toxicology conference in Dubai on Tuesday.