Myth: Some spiders are deadly.
Fact: There is no spider species anywhere that can properly be called "deadly." Obviously, a few people have died from spider venom, but I know of no species anywhere on earth capable of causing death in humans in much more than 5% of cases, even if untreated. If the person bitten obtains medical aid, death from genuine spider bite ("mystery bites" falsely blamed on spiders don't count) is almost unknown in North America and a decided rarity worldwide. See the next section for a more detailed account of Australian and Brazilian spiders. "Deadly" spiders that can incapacitate you in minutes? Only in the movies!
Information on this web site is not a substitute for professional medical advice, and should not be used to diagnose or treat a medical or health condition. You should consult a physician as to any symptoms that may require diagnosis or treatment. Genuine spider bites can sometimes require medical attention, but beyond that, several medical conditions commonly mistaken for spider bite can be even more serious. If you have what appears to be a serious spider bite, please contact your health care provider or local emergency services. If you have the actual spider that bit someone, always save it for identification by a professional arachnologist.