Your first instinct might be to panic. That fast-moving blur of legs across the floor can look frightening, especially when it suddenly appears in a bathroom, basement, or dark corner. But what you’re seeing is most likely a house centipede, and despite its unsettling appearance, it is generally not dangerous to humans.

House centipedes can actually be helpful because they feed on other pests that may be hiding inside your home. Their diet includes ants, cockroaches, spiders, silverfish, and termites. Their venom is designed for small prey rather than people, and bites are extremely rare and usually mild when they do occur.

Finding one can also be a sign that other insects are nearby. House centipedes are attracted to places where they can find food and moisture, particularly dark and damp areas. Instead of focusing only on removing the centipedes, it can be more effective to address the conditions attracting them in the first place.

To reduce their presence, lower humidity, repair leaks, seal cracks and openings, and keep rooms clean and well-ventilated. Removing their food sources can also make your home less appealing to them.

You don’t have to like the way they look, but they can provide a natural form of pest control. As the article explains, “Sometimes, what looks scary is actually helping behind the scenes.” Understanding why they appear can make their sudden appearance feel much less alarming.