Do Cockroaches Bite? What the Evidence Actually Shows
Cockroaches can bite people, but it is rare: almost every documented case involves sleeping people in severe infestations, historically on ships and in tropical housing. A 1957 Smithsonian review by Roth and Willis found cockroach bites on humans reported at least 18 times, with roaches nibbling fingernails, toenails, calluses and, in one account, children’s eyelashes. In an ordinary American home, a cockroach is very unlikely to bite you. The real health problems are allergens that worsen asthma and bacteria carried onto food.
That answer surprises people in both directions. Some are told roaches never bite, which the historical record contradicts. Others wake with marks and assume a roach did it, which is rarely the explanation. This guide sets out what the evidence actually documents, what a bite looks like, what usually causes the marks people blame on cockroaches, and where the genuine risk lies.
Claims against the evidence
| Claim | What the evidence shows |
|---|---|
| Cockroaches bite people | True but rare. Roth and Willis (1957) counted at least 18 reports, mostly from ships, tropical housing and heavily infested sleeping quarters. |
| They go for nails, eyelashes and hard skin | Consistent with the historical accounts: toenails and fingernails, calluses, corns and, in one Brazilian house, children’s eyelashes. |
| German and American cockroaches can bite | Yes. Reports from New Caledonia and Vanuatu describe Periplaneta and Blattella nibbling skin in heavy infestations, especially infants’ ears. |
| A roach bite spreads disease | No bite-borne disease is documented. The disease concern is contamination of food and surfaces by bacteria on roaches and in their droppings. |
| Bites in bed at night are probably roaches | Usually not. Bed bugs, fleas and other biters are far likelier, and bite marks alone rarely identify the insect. |
| A cockroach bite can kill you | None of the bite reports compiled by Roth and Willis describes a death caused by a bite. |
| The main health risk is the bite | No. Cockroach allergen in house dust is linked to more asthma hospitalisations in sensitised children. |
What the historical record actually documents
The key source is Louis Roth and Edwin Willis’s The Medical and Veterinary Importance of Cockroaches, published by the Smithsonian Institution in 1957 with a foreword from the US Army’s Office of the Surgeon General. Its chapter on bites opens by noting that whether cockroaches naturally bite people “has been the subject of some controversy”, then concludes that in areas where cockroaches are well controlled, bites may be rare, while in tropical areas with large populations, particularly in sleeping quarters, biting has been well documented.
Ships, sailors and gloves
The most quoted accounts come from sea. Roth and Willis cite Nicols (1870), who wrote that sailors frequently complained of having toenails, fingernails and the hard skin of their hands and feet nibbled, and Kellogg (1908), who reported ships arriving in San Francisco with sailors wearing gloves to protect their fingernails from being gnawed by the cockroaches infesting the vessel. A 1912 naval account described toenails that “have long suffered from their ravages”, and in 1936 roaches on a ship in the Orient were reported gnawing passengers’ corns.
Eyelashes, ears and infants
The eyelash story is real but singular. Roth and Willis cite an observer in Brazil who reported that cockroaches had bitten off the eyelashes of about a dozen children in the house where he was staying. Other accounts describe roaches feeding on skin flakes, the matter in the corners of sleepers’ eyes and the skin of ears and faces where it is thin. Rageau and Cohic (1956) observed that in heavy infestations Blattella and Periplaneta, the genera of the German and American cockroach, would attack people, particularly nursing infants, nibbling the skin of the ears and gnawing at scabs.
The authors’ own conclusion is measured. Many accounts, they wrote, lack the authenticity of direct personal observation, but the body of evidence cannot be ignored, and under crowded, unsanitary living conditions food-seeking cockroaches may incidentally bite people. Later reviews read the record the same way: the UC Riverside urban entomology text by Walter Ebeling says cockroaches are most likely to gnaw fingernails, eyelashes of sleeping children and callused hands and feet, but can also cause small wounds on softer skin.
Why a roach would bite at all
Cockroaches are scavengers, not blood feeders. UC IPM describes them as mostly nocturnal insects that feed on a wide range of organic matter. Everything in the bite record fits that: nails, dead skin, calluses, food grease, eye secretions and scabs are organic matter on a still, sleeping body. A cockroach biting a person is a scavenger sampling food when the population is large and other food is short, which is why bites cluster in the worst infestations.
What a cockroach bite looks like
There is very little clinical description, and most of it is old. Roth and Willis report a 1904 account that bites of the Oriental cockroach produced triangular marks on the neck, chest, elbows and feet, covered with dried blood crusts. In a 1931 experiment, Pavlovskii and Shtein induced Oriental cockroaches to bite skin moistened with sugar solution: the bite caused slight pain and itching, and 24 hours later the bitten areas were covered with scabs, which the researchers put down to mechanical damage.
So a cockroach bite, if it happens, is more of a small scraped or nibbled wound than the raised, itchy welt left by a blood-feeding insect. A neat row of itchy red bumps is not what the record describes. Any wound that becomes red, swollen or painful should be seen by a doctor.
What people mistake for cockroach bites
Most people who suspect a roach bite have woken with marks in a home where they have also seen cockroaches. The two facts feel connected, but the marks almost always have another cause. Our bite identification guide covers the full range.
When to suspect bed bugs instead
Itchy bites that appear after sleeping, on skin exposed in bed, are the classic bed bug pattern. Kentucky’s entomologists note that bed bugs feed on any skin exposed while sleeping, the face, neck, shoulders, back, arms and legs, and that the things to look for are the bugs themselves, shed skins of the nymphs and blackish faecal spots, most often in and around the bed. UC IPM adds that distinguishing bed bug bites from those of mosquitoes, fleas and spiders is difficult to impossible, so the search matters more than the mark. Our bed bug identification guide shows every stage.
Fleas and other biters
Bites clustered on the ankles and lower legs point to fleas, especially in a home with pets. If you are not sure what insect you are seeing at night, our guide to bugs that look like cockroaches covers the beetles, crickets and earwigs that get mistaken for roaches.
The real health risks
Allergens and asthma
The documented harm from cockroaches comes from what they leave behind. UC IPM states that indoor infestations are important sources of allergens and have been identified as risk factors for asthma in children, especially in multi-unit housing. A study of 476 inner-city children with asthma, published in the New England Journal of Medicine in 1997, found that 36.8 per cent were allergic to cockroach allergen, and 50.2 per cent of their bedrooms had high levels of it in dust.
Children who were both allergic to cockroach allergen and exposed to high levels had 0.37 hospitalisations a year against 0.11 for the other children, and 2.56 unscheduled asthma visits against 1.43. A nationally representative survey of 831 US homes, published in 2006, found allergen levels associated with asthma morbidity on 10 per cent of kitchen floors. Our cockroach allergen and asthma report covers the research in detail, including why the allergen persists after the insects are gone.
Food contamination
The second documented risk is contamination. UC IPM notes that American cockroaches can contact human excrement in sewers and pet droppings outdoors and are capable of transmitting bacteria that cause food poisoning, and that German cockroaches are believed to be capable of transmitting organisms including Staphylococcus, Streptococcus and coliform bacteria. Ebeling notes that Salmonella is the organism most commonly implicated. These are carried on legs, bodies and droppings, not delivered by a bite.
Our data: when cockroaches are noticed
We looked at when Americans photograph and identify cockroaches using iNaturalist research-grade records, adjusted for how much people record overall each month. American cockroach records peak in autumn, at an index of 155 in November against a low of 61 in June. German cockroach records climb through the cold months to 184 in November, with a low of 36 in May.
German cockroaches live indoors all year, so their winter rise does not mean they breed more in winter. It means people notice them, and record them, when little else is about. These records show when cockroaches were seen and identified, not how many homes are infested, but they do mark the months when people most often find themselves sharing a kitchen with one.
How to make bites a non-issue
Because bites only happen in heavy infestations, the answer to bites is the answer to infestation.
- Identify the species. German cockroaches breed indoors and need a different approach from American or Oriental cockroaches that wander in; see our cockroach identification guide.
- Remove what draws them. UC IPM advises vacuuming cracks, cleaning behind appliances and clearing crumbs, liquids and clutter; our guide to what attracts roaches goes room by room.
- Use bait, not foggers. UC IPM advises avoiding foggers, bombs and aerosol sprays, which can scatter cockroaches without killing them. Follow the label on any product you use.
- Bring in a professional for German cockroaches. Established German cockroach infestations are usually a job for a licensed professional; our German cockroach treatment guide explains why sprays fail and what works.
Frequently asked questions
What happens if a cockroach bites you?
Usually very little. The few descriptions in the scientific record describe slight pain and itching followed by a small scab, consistent with a nibbled rather than pierced wound. No disease is known to be transmitted by a cockroach bite. Clean the area and watch it; if it becomes red, swollen, hot or painful, or you feel unwell, see a doctor. A bite is also a sign of a heavy infestation that needs treating.
What smell do roaches absolutely hate?
No smell has been shown to keep an infestation away. In a 2017 laboratory study, ajowan and dill oils and compounds such as thymol, carvacrol and carvone repelled more than 80 per cent of adult German cockroaches on treated surfaces. Repelling is not killing, though: UC IPM warns that repellent sprays can simply disperse cockroaches elsewhere. Baits and sanitation are what extension entomologists rely on.
Will cockroaches crawl in your bed?
They can, particularly in heavy infestations, and historical accounts describe cockroaches entering beds in tropical housing. In most homes they stay closer to food and water: UC IPM says German cockroaches prefer kitchens, bathrooms and food preparation areas that are warm and humid. Keeping food, crumbs and dirty dishes out of bedrooms makes a bed far less attractive.
Why should you not squish a cockroach?
Squashing one will not spread an infestation, but it does smear whatever the insect carries onto the surface. UC IPM notes cockroaches can carry bacteria that cause food poisoning, so clean the spot with detergent afterwards, especially on kitchen counters. More importantly, killing the one you see does nothing for the many hidden in cracks; for German cockroaches, baits reach the population that squashing never will.
Do cockroaches bite dogs?
We found no extension or veterinary source documenting cockroaches biting healthy dogs. Roth and Willis cite observations of American cockroaches feeding on open wounds of animals in a German zoo, while noting that the observer did not suggest the cockroaches had caused the wounds. The more practical pet risk is a dog eating cockroach bait, so place baits where pets cannot reach and follow the label.
Sources
- Roth, L. M. and Willis, E. R., The Medical and Veterinary Importance of Cockroaches, Smithsonian Miscellaneous Collections 134(10), Smithsonian Institution, 1957.
- Ebeling, W., Urban Entomology, Chapter 6, Pests on or near food, University of California, Riverside.
- University of California Statewide IPM Program, Pest Notes: Cockroaches, Publication 7467.
- Rosenstreich and colleagues, The role of cockroach allergy and exposure to cockroach allergen in causing morbidity among inner-city children with asthma, New England Journal of Medicine 336: 1356 to 1363, 1997.
- Cohn, Arbes, Jaramillo, Reid and Zeldin, National prevalence and exposure risk for cockroach allergen in U.S. households, Environmental Health Perspectives 114: 522 to 526, 2006.
- Lee, Kim, Choi and Park, Repellent activity of Apiaceae plant essential oils and their constituents against adult German cockroaches, Journal of Economic Entomology 110(2): 552 to 557, 2017.
- University of Kentucky Entomology, ENTFACT-636, Bed Bugs; UC IPM Pest Notes: Bed Bugs, Publication 7454.
- Texas A&M AgriLife Extension, E-359, Cockroaches: Biology and Management, 2012.
- The Pest Control Brief analysis of iNaturalist research-grade records, pulled October 2026.
