A comparison of the toxicity of the venoms of twelve common Australian spider species on rodent vital organ systems.

1. Venom samples from twelve different Australian spider species were compared for their toxic effects on the heart and respiratory systems of anaesthetized rats. 2. The first and most serious effect of all venoms was on breathing, cardiotoxicity mostly being secondary to respiratory failure. 3. Only Atrax infensus and Selenocosmia stirlingi venoms proved highly toxic to rats, and therefore potentially toxic to humans, when single doses were used. 4. The low potency of most of the other venoms tested showed that several simultaneous spider bites would be necessary to cause significant toxicity.