Spiders are generally small and many spiderbites occur without the patient being aware of being bitten. Fortunately most such bites are trivial, but not all. There are three medically important types of spider bite in Australia. Details of red back spiders and funnel web spiders are given in the sections about the respective CSL antivenoms. The other type of spiderbite of significance is the aptly named "necrotic arachnidism". As this is not treated with antivenom, it will be discussed here.