Redbacks are considered one of the most dangerous spiders in Australia.The Redback spider has a neurotoxic venom which is toxic to humans with bites causing severe pain. There is an antivenom for Redback bites which is commercially available.
Throughout Australian history, only 14 deaths from redbacks have been recorded. However thousands of people are bitten each year across Australia, bites generally occur as a result of a person placing a hand or other body part too close to the web, such as when reaching into dark holes or wall cavities. Bites can also occur if a spider has hidden in clothes or shoes.
Bites from Redback spiders are generally characterised by extreme pain and severe swelling. The bite may be painful from the start, but sometimes only feels like a pinprick or mild burning sensation. Within an hour victims generally develop more severe local pain with local swelling and sometimes goosebumps. Pain, swelling and redness spread proximally from the site. Systemic envenoming is heralded by swollen or tender regional lymph nodes; associated features include malaise, nausea, vomiting, abdominal or chest pain, generalised sweating, headache, fever, hypertension and tremor.
Rare complications include seizure, coma, pulmonary edema, respiratory failure or localised skin infection. Severe pain can persist for over 24 hours after being bitten
Redbacks usually prey on insects but they can capture larger animals that become entangled in the web including king crickets, trapdoor spiders, and small lizards. Commonly prey stealing occurs where larger females take food items stored in other spiders' webs. Most commonly, ants stray into the web. Redback spiders are known for deadly poison and lightning speed.