Harmless in practice. It has venom and can technically bite, but its fangs struggle to break human skin and bites are very rare. It eats cockroaches, silverfish and spiders, which puts it firmly on your side.
SizeBody 25–35 mm; leg span up to about 75 mm
MarkingsFifteen pairs of very long, banded legs — far longer than any other centipede's · Greyish-yellow body with three dark stripes running its length
WhereBathrooms, basements, cupboards and behind appliances — anywhere damp, dark and holding other insects.
What it is not
A house centipede is most often confused with a species that is medically significant. If you are trying to rule those out, check these:
Fifteen pairs of very long, banded legs — far longer than any other centipede's
Greyish-yellow body with three dark stripes running its length
Body only 25–35 mm, but a leg span that makes it look much larger
Extremely fast, in bursts, with abrupt stops
Long trailing rear legs that look like a second pair of antennae
Where you’ll find it
Across the United States, in buildings almost everywhere.
Bathrooms, basements, cupboards and behind appliances — anywhere damp, dark and holding other insects.
How it behaves
It hunts rather than scavenges, running down prey and holding it with modified front legs. The speed is genuine — it is among the fastest invertebrates in a house — and the abrupt stop-start motion is what makes it so alarming to meet. It sheds legs readily when grabbed, which is a deliberate escape mechanism rather than an injury, and regrows them at the next moult. Finding one indoors means there is something for it to eat, so it is worth reading as information rather than as a problem in itself.
You’ve found one indoors
Leaving it is the rational choice, however unappealing that sounds — it is actively removing cockroaches and silverfish. If you want it gone, a glass and a card works, and reducing damp removes both the centipede and the prey that drew it. There is nothing to spray for.
Common questions
Do house centipedes bite?
Very rarely. They have venom and modified front legs to deliver it, but those struggle to penetrate human skin. A bite feels roughly like a bee sting and needs nothing beyond washing it.
Should I kill it?
There is a good case for not. It eats cockroaches, silverfish, firebrats and spiders, and a house with one in it usually has fewer of those. Its presence is a signal about what else is there.
Why does it have so many legs, and why did it drop one?
Fifteen pairs, and it sheds them deliberately when grabbed so it can escape. The lost legs regrow over subsequent moults.
Is it a centipede or a millipede?
A centipede: one pair of legs per body segment, and a hunter. A millipede has two pairs per segment, moves slowly and eats decaying plant matter.
Cecile Roux · CC-BY-SA