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Are White-Tailed Spiders Dangerous?

Written by PestMan Editorial TeamTechnical review pendingPublished Updated

Quick answer

White-tailed spiders are not considered dangerous. Their bite can cause local pain, redness, swelling and itching, but research on confirmed bites found no cases of the "flesh-eating" ulcers they are often blamed for. See a doctor about any wound that is getting worse, because other causes such as infection need proper treatment.

Why this happens

The belief that white-tailed spiders cause necrotic ulcers spread in the 1980s and 1990s. A study of confirmed bites, where the spider was caught and identified, found mostly mild effects and no necrotic ulcers.

White-tailed spiders hunt other spiders at night and often wander indoors, which is why they turn up in bedding, towels and clothes left on the floor. Most bites happen when a spider is trapped against skin.

What you may be seeing

  • A slender, cigar-shaped dark grey spider with a pale spot at the tip of its body.
  • Spiders on walls, in bathrooms or in bedding at night.

What you can do

  • Shake out towels, clothes and bedding left on the floor.
  • Reduce other spiders (their prey) by removing webs regularly.
  • Relocate white-tailed spiders outside with a container and card.
  • For a bite, wash the area, apply a cold pack and see a doctor if pain or swelling is severe or the wound worsens.

When professional help may be needed

Pest control is rarely needed for white-tailed spiders alone. Reducing other household spiders and sealing gaps is usually enough.

Species mentioned

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Sources & further reading

PestMan provides general information only and does not replace licensed pest-management, medical, veterinary or structural advice. Always read and follow product labels. Read our disclaimer.