Antivenom (also known as antivenin) is a specialised medical treatment used to counteract the toxic effects of venom injected through bites or stings by venomous creatures such as snakes, spiders, or marine animals. In Australia, snake antivenoms are most commonly used and are produced by injecting small, non-lethal amounts of venom into animals—usually horses—so they develop antibodies. These antibodies are then harvested, purified, and formulated into injectable antivenom.

Each type of antivenom is designed to target specific venom components. For example, Australia produces monovalent antivenoms that treat bites from specific snakes (e.g. taipan, tiger snake, brown snake), as well as a polyvalent antivenom used when the snake species is unknown. Antivenom works by binding to the venom’s active toxins in the bloodstream, neutralising them before they can cause further harm to the nervous system, blood clotting, or organs.

In Australia, antivenom is administered in a hospital setting by trained medical personnel, typically through an intravenous (IV) line. Timely administration can significantly reduce the severity of symptoms, speed up recovery, and save lives. However, antivenom is not without risk—it can cause allergic reactions or serum sickness, so its use is carefully managed.

First aid for snake bite plays a critical role in supporting the casualty until antivenom can be administered. The pressure immobilisation technique (PIT), for instance, helps delay the spread of venom, buying precious time for emergency services to arrive.