Cellar spiders are not poisonous, although the correct terminology would be venomous, which they also are not. Cellar spiders are not medically important spiders because they are not known to bite people. Nonetheless, an urban myth persists that cellar spider venom is among the deadliest on the planet.

Should I kill cellar spiders?

Both build webs where they lie in wait for prey to get caught. Cellar spiders sometimes leave their webs to hunt other spiders on their turf, mimicking prey to catch their cousins for dinner. ... So killing a spider doesn't just cost the arachnid its life, it may take an important predator out of your home.

Are cellar spiders poisonous to humans?

Although their bites are harmless to humans, their webs are unsightly and profuse: unlike other spider species, cellar spiders prefer to live within close proximity to one another, creating troublesome communities within human dwellings.