Rodenticide Poisoning

Written by Katie

March 23, 2021

Rodenticide, rat or mouse poison, is one of the most common poisonings among pets. There are different types of poison, knowing which one your pet ingested is extremely important. Having the packaging available or knowing the active ingredient when contacting your veterinarian is essential to the pet’s treatment. The amount and approximate time of ingestion is also helpful in determining the treatment course.

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Rodenticide comes in a wide variety of color (green, blue, red, etc.) and in many forms (pellets, blocks, grain, etc.). Products that look the same or have a similar name may have different active ingredients. There are four common active ingredients in mouse and rat poisons: long-acting anticoagulants, cholecalciferol, bromethalin, and phosphides.

Long-acting Anticoagulants

This is the most common and widely known type of rodenticide. The are several different active ingredients, all of which act like a blood thinner, preventing clotting, and can result in internal bleeding. When ingested, it typically takes 3-5 days before symptoms appear. Common signs include lethargy, coughing, difficulty breathing, weakness, pale gums, vomiting, nose bleeds, bruising, bloody urine, swollen joints or extremities, not eating, and bleeding from gums.

Treatment for this type of rodenticide includes Vitamin K, which supports the body’s natural blood clotting ability. Supportive care such as blood transfusions, IV fluids, and other treatments may be necessary depending on the severity of symptoms and amount of ingestion.


Rodenticides with bromethalin as the active ingredient cause brain swelling and neurological symptoms. This type of rodenticide does not have an antidote. Urgent veterinary care is crucial and may include decontamination, IV fluids, and special drugs to decrease brain swelling. Ingestion can cause serious, long term effects. Symptoms include lethargy, weakness, ataxia (acting uncoordinated), tremors, seizures, paralysis and even death.


Cholecalciferol is one of the most potent types of rodenticide. The active ingredient elevates the blood calcium to a dangerous level. If left untreated this can cause kidney failure. Signs may not show up for 1-3 days, by which time significant damage can already occur. Symptoms can include increased thirst and urination, lethargy, decreased appetite, and vomiting. Acute kidney failure can develop 2-3 days after ingestion. This form of rodenticide does not have an antidote and a small amount can cause severe clinical signs and death. Supportive care and hospitalization are required, but still may not produce a positive outcome.


Phosphides are commonly found in mole and gopher baits as well as rat and mouse poison. When mixed with stomach acid the deadly phosphine gas is released. Food in the stomach increases the amount of gas produced. A very small amount of phosphides can cause severe poisoning and immediate veterinary care is required. Extreme caution must be taken as the vomit from a patient will release the poisonous gas and is dangerous to humans as well. Inducing vomiting is better left to veterinary professional, but if vomiting occurs, keep the pet and yourself in a well-ventilated area. Administration of antacids can decrease the amount of gas produced. Symptoms of ingestion include drooling, nausea, stomach bloating, vomiting, abdominal pain, shock, collapse, seizure, liver damage, lung damage, and death.

If you believe your pet has ingested any poison or toxin, have the label or packaging available and contact an emergency veterinarian or the Pet Poison Helpline immediately. Never give home remedies like milk or food without consulting a veterinarian or Pet Poison Helpline specialist first. Likewise, never induce vomiting in your dog or cat without consultation, as it can be more dangerous to your pet and you.

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