Few spiders cause as much confusion—and concern—as the yellow sac spider. These pale, fast-moving arachnids often sneak into homes, leaving many homeowners wondering: Are they dangerous? Should I be worried? At Pest Jam, we break down everything you need to know about yellow spiders, from their appearance and behavior to whether their bite poses a real threat.
What Is a Yellow Sac Spider?
The yellow sac spider (scientific name: Cheiracanthium mildei or Cheiracanthium inclusum) is a small, pale yellow or beige spider commonly found in homes across North America. Unlike web-building spiders, these hunters do not spin traditi Yellow Spideronal webs—instead, they create silken sacs (hence their name) where they hide during the day.
Key Identification Features:
✔ Color: Pale yellow, light green, or beige (some have faint stripes).
✔ Size: About ¼ to ½ inch long (smaller than a penny).
✔ Legs: Long, slender legs with slightly darker tips.
✔ Eyes: Eight small eyes arranged in two rows.
✔ Web: No orb web—instead, they build small silk retreats in corners or under leaves.
If you see a small yellow spider darting across your walls at night.
Yellow Sac Spider vs. Other Common Spiders
| Feature | Yellow Sac Spider | Black & Yellow Garden Spider | Crab Spider |
| Color | Pale yellow/beige | Bright yellow & black | Yellow/white |
| Web | Silken sacs only | Large orb webs | No web |
| Behavior | Wanders at night | Sits in web | Ambushes prey |
| Bite Risk | Mildly venomous | Harmless | Harmless |
Are Yellow Sac Spiders Dangerous?
Do They Bite?
Yes, but only if provoked. These spiders are shy and prefer to flee rather than attack. Most bites happen when they’re accidentally pressed against skin (e.g., in clothing or bedding).
Yellow Sac Spider Bite Symptoms
Symptoms may include:
✔ Sharp pain at the bite site
✔ Redness and swelling
✔ Mild itching or burning
✔ Small blister in rare cases
Unlike brown recluse or black widow bites, yellow sac spider bites are not medically significant and usually heal within a few days.
Where Do Yellow Sac Spiders Live?
These spiders are common household invaders, especially in:
✔ Corners of ceilings & walls
✔ Behind furniture
✔ Inside closets & storage boxes
✔ Under leaves in gardens
They’re frequently found in Ontario, Quebec, Alberta, and BC, but they exist across Canada and the U.S.
How to Get Rid of Yellow Sac Spiders
1. Remove Their Hiding Spots
✔ Declutter storage areas.
✔ Seal cracks around windows & doors.
✔ Vacuum regularly (especially corners).
2. Natural Repellents
✔ Peppermint oil (spray near entry points).
✔ Diatomaceous earth (sprinkle in spider-prone areas).
Professional Pest Control
If you have an infestation, Pest Jam can help with targeted treatments to keep spiders out.
Preventing Future Infestations
✔ Install window screens.
✔ Keep outdoor lights off (they attract prey).
✔ Store firewood away from the house.
While yellow sac spiders look unsettling, they’re not highly dangerous. If you find one, simply relocate it outside. For persistent problems, Pest Jam offers safe, effective solutions.
Spotted a yellow spider? Identify first—then take action if needed!
