Rodenticides: Keep critters at bay but keep children away

This year, four children in Texas died after an unpleasant smell was noticed in their home. It was later discovered that the landlord had sprayed rodenticides around the outside of the house. How could this have been prevented?

In another news report, a 1-year old boy experienced vomiting and green diarrhea after his mother found an opened container of rodenticide in the home. What should be done when an accidental ingestion is suspected?

What are rodenticides?
Rodenticides, also known as rat poisons, are chemical pesticides that are used to control mice and rats, but also squirrels, rabbits, gophers and other rodents. They are made up of a flavoring, such as peanut butter, and an active ingredient that kills pests. All rodenticides can be toxic when ingested by humans and animals. There are some that can also be toxic if they contact the skin or if they are inhaled. Rodenticides are usually sold as small blocks or as a paste contained within a bait station. They can be used for indoor or outdoor use.

Why are rodenticides a health concern?
Pediatric poisoning is a common cause of emergency room visits. Rodenticides are one of the top ten chemicals that result in these visits. In 2006-2015, there were 34,163 rodenticide exposures reported in children under 6 years of age. The high prevalence of rodenticide poisonings may be attributed to the bright colors, scents or flavors used to attract rodents which also make them attractive to young children. Although the Environmental Protection Agency (EPA) has banned several rodenticides and requires bait stations to be tamper-free, exposures continue.

How do rodenticides work?
There are three categories of rodenticides:
● First-generation anticoagulants: warfarin, chlorophacinone, and diphacinone.
● Second-generation anticoagulants: brodifacoum, bromadiolone, difenacoum, and difethialone.
● Non-anticoagulants: bromethalin, cholecalciferol and zinc phosphide.

Anticoagulants are also known as blood thinners. They prevent blood clotting, which can cause excessive bleeding. Second-generation anticoagulants, also called “superwarfarins,” are more hazardous than first-generation anticoagulants and are not sold in the residential consumer market.

Non-anticoagulants have different methods of affecting pests:
Bromethalin prevents energy mechanisms in nerve cells which results in brain swelling.

Cholecalciferol is also known as vitamin D3. In small doses, it is used to maintain bone health. However, very large doses of cholecalciferol can be toxic because it increases calcium to abnormally high levels in the blood.

Zinc phosphide releases phosphine gas in the stomach which causes cell death.

What are the signs of rodenticide poisoning?
Anticoagulants, when ingested in large quantities, can present as nosebleeds, dark stools, bloody urine and bruising. Second generation anticoagulants can result in massive bleeding with a single dose.

Bromethalin poisoning is rare. Symptoms can include confusion and loss of consciousness.

Cholecalciferol toxicity has not yet been reported. When ingested in massive quantities, it can possibly injure the kidneys. Kidney damage can result in high blood pressure, excessive thirst and excessive passage of urine.

Zinc phosphide can be toxic when either ingested or inhaled. Most commonly, zinc phosphide causes vomiting, which helps reduce its effects. In higher doses, symptoms include shortness of breath, coughing and an irregular heartbeat (heart arrhythmia). Zinc phosphide can also damage the kidneys and the liver. Skin irritation is rare but can present as a burn.

How can rodenticide poisoning be prevented?
● Always follow the label to minimize exposure. The EPA mandates that all rodenticides be labelled with information about proper storage and disposal of leftovers. First Aid instructions are also present on labels and can be used in case of exposure.
● Always store pesticides away from the reach of children and pets in a locked garden shed or utility cabinet.
● Place traps or baits only in locations where children do not play or crawl.

What should be done if you suspect accidental ingestion?
Call the Poison Help line at 1-800-222-1222. Call 911 if the person is not breathing.

Any amount of accidental ingestion should be reported, even when there are no signs or symptoms of rodenticide poisoning. Have information about the suspected rodenticide available. This information can be important to guide appropriate medical treatment.

Where can you find more information?
National Pesticide Information Center (NPIC)
Centers for Disease Control and Prevention (CDC) – Rodenticides and Child SafetyTips


May 2017. This blog post was written by Jasmine Partida, Medical Student at the University of Illinois at Chicago College of  Medicine and edited by Dr. Susan Buchanan.



McClure, Robert . “Rat poisons endanger 10,000 U.S. children every year.” Environmental Health News. N.p., 14 Dec. 2010. Web. 6 May 2017.

Mohney, Gillian. “How Water Poured on Rodenticide Caused 4 Deaths in a Texas Home.” Online Posting. ABC News. N.p., 3 Jan. 2017. Web. 6 May 2017.

Mowry, PharmD, James B., and Daniel A. Spyker PhD, MD, Daniel E. Brooks MD, Naya McMillan DrPH, MS & Jay L. Schauben PharmD. 2015 Annual Report of the American Association of Poison Control Centers’ National Poison Data System (NPDS): 33nd Annual Report, Clinical Toxicology, 54:10, 924-1109, Web. 30 Apr. 2017.

Roberts, M.D., M.P.H, James R., and J. Routt Reigart, M.D. Recognition and Management of Pesticide Poisonings. 6th ed. Washington, DC: U.S. Environmental Protection Agency, 2013. Web. 30 Apr. 2017.

Vantassel, Stephen, Scott Hygnstrom, and Dennis Ferraro. Bait Stations for Controlling Rats and Mice. Lincoln: U of Nebraska-Lincoln, 2006. Print.

Medical Management Guidelines for Phosphine. Agency for Toxic Substances and Disease Registry, 21 Oct. 2014. Web. 30 Apr. 2017.

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“Chapter 13: Storage and Disposal.” Label Review Manual. N.p.: Environmental Protection Agency, n.d. 13.1-13.55. July 2013. Web. 5 May 2017.

Cholecalciferol. Hazardous Substances Data Bank, 11 May 2006. Web. 30 Apr. 2017.


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