The Red Back spider (Latrodectus hasselti) belongs to the world-wide genus of widow spiders (genus Latrodectus). Species are found on all continents, excluding Antarctica. The envenomation syndrome seen following the bite of a widow spider is similar for all species of this genus.

Latrodectism, the clinical syndrome of widow spider envenomation, is probably the most common medically important envenomation seen in Australia. Despite this, it is often misdiagnosed and poorly managed by medical practitioners, leaving patients with distressing symptoms for prolonged periods of time.

Red Back spider antivenom is probably the most commonly administered antivenom in Australia. Currently, there is considerable debate over the preferred route of administration for this antivenom and clinical trials are currently under way to resolve this issue.