Key takeaways
- About a quarter of the microorganisms isolated from cockroaches are foodborne pathogens, according to a 2020 scientific review.
- In a hospital study, 99.4% of German cockroaches carried medically important microbes, including multidrug-resistant bacteria.
- Cockroach droppings, shed skins and body parts contain allergens that UF/IFAS says can trigger asthma attacks, even fatal ones in extreme cases.
- Heavy infestations bring odors, damaged books and clothing, rare bites and real stress for the people living with them.
- Misused insecticides are a danger of their own; targeted baits and sanitation lower both the roaches and the chemical risk.
In this article
Cockroaches are dangerous in seven main ways: they carry disease-causing germs onto food and surfaces, they can harbor antibiotic-resistant bacteria, their droppings and body parts trigger allergies and asthma, they foul food and belongings with odors and droppings, they occasionally bite in heavy infestations, they wear on mental health, and the chemicals people use against them can become a hazard of their own.
Most of these dangers stay out of sight. Roaches feed at night and hide by day, and the allergens and microbes they leave behind are invisible. In South Florida, where roaches are active every month of the year, the exposure is constant unless you deal with the infestation itself. This guide walks through each danger, how serious it is and what actually reduces it.
1. Germs Carried Onto Food and Surfaces
Cockroaches move between the dirtiest and cleanest parts of a building. UF/IFAS reports that the American cockroach can build up to more than 5,000 roaches in a single sewer manhole, and that at least 22 species of disease-causing bacteria, viruses, fungi and protozoans, plus five species of parasitic worms, have been isolated from field-collected American cockroaches.
A 2020 review in Environmental Health Insights found that about a quarter of the microorganisms isolated from cockroaches are foodborne pathogens. The list includes:
- Salmonella, including the serovar that causes typhoid fever
- E. coli O157:H7
- Shigella dysenteriae, a cause of dysentery
- Staphylococcus aureus and Bacillus cereus
- Rotavirus and the parasite Cryptosporidium parvum
Roaches move these microbes on their bodies, in their droppings and in regurgitated food. The same review is careful to add that their role in human infections is poorly understood and has been debated for years, so think of roaches as a possible route of contamination rather than a proven main cause of food poisoning. Our article on how cockroaches spread Salmonella traces that route step by step.
2. Antibiotic-Resistant Bacteria
One of the least known dangers is that cockroaches can carry bacteria that antibiotics no longer kill easily. Researchers at the All India Institute of Medical Sciences compared German cockroaches caught in a hospital with roaches from homes, in a study published in Epidemiology and Infection.
Source: Fotedar et al., Epidemiology and Infection
Nearly every roach in both groups carried microbes of medical importance. Hospital roaches more often carried heavy bacterial loads, and they harbored multiple drug-resistant bacteria. The authors concluded that the variety of resistant species suggests cockroaches may be involved in transmitting drug-resistant bacteria, and that hospital roaches can act as potential vectors of medically important bacteria. Fungi and parasites turned up too, though less often.
This is why pest control is part of infection control in hospitals, clinics and nursing homes, where Toro provides health care pest control. At home, the same principle applies on a smaller scale: anything a roach touches should be treated as contaminated.
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3. Allergies and Asthma
For many families, allergens are the most important cockroach danger, because the exposure is daily and does not require contact with a live roach. The EPA explains that droppings and body parts of cockroaches can trigger asthma, that certain proteins in their feces and saliva cause allergic reactions, and that cockroach allergens likely play a significant role in asthma in many urban areas. The EPA also notes that cockroaches are common in the southern United States.
UF/IFAS adds that allergens in feces, shed skins, antennae and legs can cause rashes and other allergic reactions, and in extreme cases can trigger fatal asthma attacks. UF/IFAS also notes that vacuuming removes the skins and feces that cause cockroach allergies, so cleanup is part of control. For symptoms, testing and cleanup, see our guide to asthma and allergies caused by cockroach infestations.
The Everyday Toll: Odors, Bites and Stress
Not every cockroach danger involves germs. Three more build up the longer an infestation lasts.
4. Odors, Spoiled Food and Damaged Belongings
Cockroaches do not chew through walls like termites, but they ruin things. According to UF/IFAS, cockroaches damage books, clothing and food, and their oily secretions and feces create an offensive odor that can transfer to dishes, food and clothes. German cockroaches also contaminate food with feces and defensive secretions, and their diet even includes book bindings.
There is a second, sneakier problem: cockroach feces contain an aggregation pheromone that attracts other cockroaches. Droppings left in cabinets and drawers effectively advertise the spot to more roaches. That is why UF/IFAS recommends vacuuming and scrubbing with hot, soapy water, which removes both allergens and pheromone-laden droppings.
5. Bites in Heavy Infestations
Cockroach bites are rare. Still, UF/IFAS reports that in extremely heavy German cockroach infestations, roaches have been reported to bite people and to feed on food residue on the faces of sleeping people. If you reach that point, the infestation needs professional treatment right away.
6. Stress and Quality of Life
The psychological toll is real. UF/IFAS notes that some scientists suggest cockroach infestations cause psychological stress and change behavior: residents avoid entertaining and stay out of the kitchen at night for fear of meeting a roach. Add poor sleep, embarrassment and the frustration of treatments that keep failing, and a roach problem can affect a household long before anyone gets sick.
7. Risks From Do-It-Yourself Chemicals
The fight against roaches can create its own danger. The EPA reminds families that insecticides and pesticides can harm people as well as pests, and recommends pest management methods that pose less risk. UF/IFAS puts it simply: all insecticides are poisons.
Common mistakes that raise the risk:
- Spraying counters, dishes or food prep areas
- Spraying into electrical outlets
- Relying on sprays and foggers instead of targeting the cracks where roaches hide
- Mixing products or making homemade chemical blends
- Storing products where children or pets can reach them
Chemicals alone also fail. UF/IFAS calls chemical use alone the least effective control method and warns it can lead to insecticide resistance, so the risk rises while the roaches stay.
How Serious Is Each Danger?
| Danger | How it happens | Who is most affected | What reduces it |
|---|---|---|---|
| Germs on food | Roaches walk, defecate and regurgitate on food and surfaces | Young children, older adults, people with weak immune systems | Sealed food, clean surfaces, roach control |
| Drug-resistant bacteria | Roaches pick up resistant bacteria in contaminated places | Hospitals, clinics, care homes | Professional programs, sanitation |
| Allergies and asthma | Proteins in droppings, saliva, skins and body parts | Children and adults with asthma or allergies | Roach control plus thorough cleanup |
| Odors and damage | Secretions, droppings and feeding | Everyone in a heavy infestation | Remove harborage, clean and treat |
| Bites | Feeding in extremely heavy infestations | People sleeping in heavily infested homes | Immediate professional treatment |
| Stress | Constant sightings and failed treatments | The whole household | A plan that works the first time |
| Chemical misuse | Sprays and foggers used carelessly | Children, pets, people with asthma | Baits in cracks, label directions, professionals |
How to Lower the Dangers at Home
The same steps protect against nearly every danger on the list, because they shrink the roach population and the debris it leaves.
- Remove water. Fix leaks, dry the sink at night and empty refrigerator drip pans. UF/IFAS calls water the most critical factor for roach survival.
- Remove food. Store food and pet food in sealed containers, wash dishes promptly and take out the trash nightly.
- Remove shelter. Discard cardboard boxes, reduce clutter and seal cracks around pipes, cabinets and shared walls.
- Clean up allergens. Vacuum and wipe cabinets, drawers and baseboards with hot, soapy water, especially after a treatment.
- Choose targeted control. UF/IFAS calls baits the most highly recommended option because they are targeted and reduce unnecessary pesticide exposure. Never spray where bait is placed.
When to Call a Professional
Call for help if you see roaches during the day, find droppings or egg cases in more than one room, see small nymphs, or still have roaches several weeks after cleaning and baiting. Those signs point to a breeding population that over-the-counter products will not reach. For a deeper look at the health side, our guide to the health risks of cockroaches in South Florida homes covers who is most vulnerable.
Toro Pest Management has protected South Florida homes and businesses since 1969. A technician inspects kitchens, bathrooms, appliances and drains, identifies the species and places baits and growth regulators in the cracks, voids and appliances where roaches live, applied according to the label, then returns to treat new nymphs as eggs hatch. Homeowners can choose Total Home Protection Gold 365, an every-other-month service inside and outside the home, and businesses can get a program through commercial pest control. If the bugs come back, so will Toro, at no additional cost to you.
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305-594-4767Frequently Asked Questions
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Sources
- Cockroaches and Their Management, UF/IFAS Extension
- German Cockroach, Blattella germanica (Linnaeus) (Insecta: Blattodea: Blattellidae), UF/IFAS Extension
- American Cockroach, Periplaneta americana (Linnaeus), UF/IFAS Extension
- Asthma Triggers: Gain Control, U.S. Environmental Protection Agency
- Cockroaches (Blattella germanica) as Carriers of Microorganisms of Medical Importance in Hospitals, Epidemiology and Infection (Cambridge University Press)
- Cockroaches and Food-borne Pathogens, Environmental Health Insights (via University of Ghana UGSpace)
Educational content. This article is for general information about pests in South Florida and is not medical, legal or professional advice. If you have a bite, sting or allergic reaction, contact your doctor; in an emergency, call 911. Pest problems vary from home to home, so a licensed professional should inspect before treatment. When using any pesticide, always read and follow the product label.
