Some of the most dangerous spiders in the world include the Brazilian wandering spider, the black widow spider and the brown widow spider. The brown recluse spider, the six-eyed sand spider, the Chilean recluse spider and the northern funnel web spider are also extremely venomous, according to Outdoor Life.
The Brazilian wandering spider possesses the most neurologically toxic venom of any known spider, reports Spidersworlds.com. Its venom includes high serotonin levels that cause a painful bite that can result in muscle shock, adds Outdoor Life. The black widow spider caused 63 deaths in the United States during the 1950s before anti-venom was invented.