Compare leg arrangement, body shape, movement and moisture clues before choosing a response.
Centipede or millipede? Start with these clues
A long body and many legs can belong to two quite different animals. A centipede is a predator; a millipede usually recycles decaying vegetation. Both can turn up near a damp doorway, but their food and behavior explain different inspection priorities. For a close look at centipede features, use our centipede identification guide.
Watch from a distance rather than picking the animal up to count legs. Note whether the legs project sideways, whether the body looks flat or rounded, and whether it runs or slowly coils. A photograph showing the entire body is more useful than a description of color alone. Neither animal’s name is a dependable leg count.
A practical comparison of appearance and movement
| Clue | Centipede | Millipede |
|---|---|---|
| Leg arrangement | One pair on most leg-bearing segments | Two pairs on most body segments |
| Typical outline | Flattened, with legs projecting outward | Often cylindrical, with shorter legs beneath the body |
| Movement | Fast runner | Slower; may coil when disturbed |
| Food | Insects and other small arthropods | Mostly decaying plant matter |
House centipedes are especially recognizable by their very long legs. Other centipedes look more compact, so short legs do not automatically mean millipede. There are also flat-backed millipedes. Use several features together; the table describes useful tendencies, not a complete species key.
Counting every leg is unnecessary for household identification. The arrangement along the body distinguishes the groups more reliably than a total. Young animals and adults may differ in size and development, and a partly obscured or damaged specimen can be difficult to identify. Avoid assuming an unfamiliar large specimen is a common house centipede.
| Clue | House centipede | Common household millipedes |
|---|---|---|
| Color and antennae | Brownish or grayish-yellow, often with three dark stripes; long slender antennae. | Often dark brown; other species have different colors. |
| Legs and body outline | An adult house centipede has 15 pairs of conspicuously long legs. | Many common kinds are cylindrical, but garden or greenhouse millipedes can have a flattened back and flanges along the sides. |
These examples refine the comparison, not a color-only species test. Use leg arrangement and several features together.
For scale, UMN describes a fully grown house centipede as more than 1 inch long and its common millipede example as about 1–1½ inches. These examples overlap and do not give universal size limits for either group. Compare leg arrangement, body form and other features rather than identifying an animal from length alone.
For a leg-count comparison, UMN’s common household millipede example has up to 400 very short legs, alongside its adult house-centipede example with 15 pairs of long legs. These are the guide’s examples, not universal totals or species limits. Leg arrangement, body outline and several other features are more useful than counting every leg.
Diet, development and why sightings repeat
Centipedes hunt small insects and spiders, usually at night. Their presence can justify looking for other insects, but one centipede does not prove a cockroach or bed bug infestation. They are useful predators outdoors and cannot be relied on as a household treatment program.
Millipedes feed chiefly on decaying vegetation in moist soil and litter. They are not wood-destroying termites. UF/IFAS describes eggs laid in soil and young that pass through successive stages before adulthood. Centipedes also develop from eggs, with young resembling adults; development and lifespan depend on the species and conditions. Some centipedes are long-lived, but a universal lifespan for every household millipede is misleading.
Recurring arrivals can come from a favorable outdoor habitat rather than a new indoor breeding population. Read more about centipede biology when distinguishing an occasional visitor from continuing activity. A sighting after one animal is removed does not by itself establish what caused the next animal to enter.
Where to inspect indoors and outdoors
Outdoors, inspect the conditions around pots, stored boards, leaf litter, mulch and wood near the foundation. Both groups use damp shelter; millipedes also find food in decomposing plant matter. After rain, numerous millipedes can move toward buildings and enter small openings. Record whether sightings follow storms or happen independently of weather.
Indoors, start with bathrooms, laundry areas, closets beside plumbing, ground-level doors and garages. Look for a leak, condensation, a worn door seal or wet materials against an exterior wall. Potted plants brought indoors are another place to check. Distinguish insects caught in the same room from assumptions about what the centipede is eating.
Our guide to repeated centipede sightings explains useful inspection questions. Keep a short log with the date, room and number seen. Several observations from the same doorway after rain suggest a different response from repeated centipedes deep inside a damp room.
Millipedes that enter a dry home often die soon afterward. Repeated live millipedes inside warrant checking for excess moisture as well as outside entry routes. Sweep or vacuum arrivals rather than inferring an indoor breeding colony from their presence alone; reducing damp shelter and access addresses different conditions from removing one animal.
Bites, defensive fluids and exposure precautions
Centipedes use venom to subdue prey, and larger species can cause painful bites. Avoid handling them or trapping them against skin. Appearance alone cannot predict how someone will react, and there is no reliable promise that symptoms disappear within a few hours.
Millipedes do not sting or inject venom like a centipede, but some release defensive chemicals. These can irritate skin and eyes and can stain skin brown; the effects vary by species and exposure. Do not crush them with bare hands or allow a pet to mouth them. If fluid contacts skin, wash it off. If millipede fluid enters an eye, rinse with plenty of water for at least 20 minutes and get medical attention right away. For other significant or continuing symptoms, contact Poison Control or a healthcare professional. Contact a veterinarian for a pet exposure.
These animals are household nuisance arthropods rather than blood-feeding parasites. That distinction does not make every exposure harmless. Breathing difficulty, faintness or a severe reaction requires urgent medical help; identification advice should never delay it.
Reduce moisture, access and shelter
Repair leaks and investigate condensation before buying a spray. Use ventilation or suitable dehumidification where moisture persists, and keep drainage directed away from the house. A dry room does not prove the wall cavity beside it is dry. If moisture returns, have the underlying plumbing, roof or HVAC problem assessed.
Repair door sweeps and weatherstripping, seal appropriate nonventilation gaps around utility penetrations, and keep drainage openings functional. Move damp organic debris and stored wood away from exterior walls. Thin excessive mulch instead of sealing moisture beneath it. Check pots and containers before bringing them inside.
For a small indoor nuisance, mechanical removal with a vacuum or dustpan avoids unnecessary room-wide pesticide application. Keep any monitoring devices away from children and pets. Pesticides, when warranted, must be labeled for the pest, site and method; broad perimeter spraying is not an automatic answer to rain-driven millipede migration.
Where centipedes are seen, appropriately placed sticky monitors can help record activity. With repeated sightings, inspect for other insects and spiders, identify the prey actually present and address it as well as moisture. Keep monitors inaccessible to children and pets. A single centipede does not diagnose a cockroach or bed-bug infestation, and these measures do not guarantee predator suppression.
When an inspection is useful
Get help when arrivals persist, moisture cannot be explained, or several rooms show activity. Bring the log and photographs, and explain whether repairs or cleaning changed the pattern. Note moisture and prey clues associated with indoor centipede activity so the inspection can address conditions as well as the insects.
An inspection should distinguish the animal, likely entry routes, outdoor habitat and any indoor prey activity. Ask which repairs you can make, how activity will be monitored, and what finding would justify treatment. Compare the next observations with the starting log. Professional products do not guarantee a permanent barrier, and a spring/fall schedule should not be prescribed without the property’s findings.
Frequently Asked Questions
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Can centipedes and millipedes infest a house at the same time?
Yes. Both may appear where damp shelter and openings are present. Centipedes hunt small arthropods while millipedes mainly feed on decaying vegetation. Seeing both does not establish a predator-controlled population; inspect moisture and entry routes.
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Do centipedes or millipedes carry diseases?
University of Georgia Extension describes centipedes and millipedes as not carrying diseases that affect people, animals or plants in its household-pest guidance. That differs from saying every specimen is sterile or safe to handle. The immediate exposure concerns are a centipede bite and irritation from some millipedes’ defensive chemicals. Avoid handling them and obtain medical advice for significant symptoms or eye exposure.
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Will killing centipedes attract more centipedes?
Seeing another centipede after killing one does not establish that the death attracted it. UMN Extension recommends removing centipedes when needed while reducing damp shelter and the insects they eat; it does not identify killing as the explanation for recurring arrivals. Check moisture, prey and entry gaps instead of assuming a pheromone effect. Removing one animal alone leaves those supporting conditions in place.
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How long do centipedes and millipedes live?
Lifespan varies by species and conditions. UF/IFAS describes some centipedes living up to six years; that is not a verified range for every house centipede or millipede. Development information is more useful for understanding persistence than a universal lifespan.
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Are millipedes poisonous to pets like dogs or cats?
Keep dogs and cats from touching or mouthing millipedes. Missouri’s wildlife guidance specifically warns against pet contact with cyanide-secreting flat-backed species. That does not establish the dose or toxicity of every species for a particular dog or cat. If contact or symptoms occur, get veterinary advice promptly; do not apply human irritation guidance or home remedies to a pet.
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What is the fastest way to get rid of millipedes after heavy rain?
Remove indoor arrivals mechanically, inspect ground-level door seals and gaps, and reduce wet organic material and drainage problems near the house. Persistent migrations merit an inspection. Use pesticides only when justified and according to the product label.
Vincent founded On Demand Pest Control in 2017 and is a Florida Certified Operator in all four state categories. He treats pest control as a systematic problem to solve, not a symptom to spray. Read Vincent’s full bio →
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