Spider Bites - Treatment and Prevention Venomous spiders inject offensive poisons into their victims. These are meant to disable or kill a victim so it can be eaten, and to soften or predigest the victim.
Most spider bites occur at night when a spider passes over a sleeping victim.
When discovered hours later, it is usually as a sore red bump. Most spiders are shy and harmless to humans, and will not attempt to bite unless trapped or held. Wholesale destruction of spiders should be avoided, if possible. Some southern states not only tolerate spiders but encourage them for their nuisance insect control. All spiders produce venom that is poisonous to their normal prey of insects, mites and other small arthropods.