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Autumn Hazards for Pets: Rat and Mouse Poisons

Fall is here–the season of changing colors, apple orchard visits, and pumpkin spice lattes! During this time of year, rodents also feel a chill in the air and look for a warm place to call home. Many people place rat and mouse-killing bait around homes to eliminate infestations. Here’s what you should know about the four general toxic forms of rat and mouse baits.

First and foremost, early detection is key! If you see your pet eat rodent poison (or even think it could have) contact a vet right away. Often, the first step is to induce vomiting. In the clinic, we do not use hydrogen peroxide as it can cause stomach and esophagus irritation. However, if you live far from a vet, hydrogen peroxide may be the best option. Call an animal poison control center for assistance with dosage. 

1. Anti-coagulants 

  • What do they do? Cause bleeding both inside and outside the body
  • Names to watch for: brodifacoum, bromadiolone, diphacinone, warfarin
  • How long before my pet starts to show symptoms? 
    • 36-48 hours until bloodwork shows abnormal results
    • 3-5 days until poisoning symptoms
  • Symptoms: Pale gums, weakness, difficulty breathing, coughing, bloody urine, bloody feces
  • Treatment: This is the only rat bait with a specific antidote, Vitamin K1, which is given every day for several weeks after the poisoning. However, if a pet is already sick from bleeding, blood transfusion is often needed prior to giving Vitamin K1.

I do not promote using toxic rodenticides; however, from my perspective, anti-coagulants are better than others because at least there is an antidote! If you must use rat poison, please consider an anti-coagulant product.

2. Neurotoxins

  • What do they do?  Cause brain and spinal cord swelling.
  • Name to watch for: Bromethalin
  • How long before my pet starts to show symptoms? 
    • Large amounts cause symptoms within 2-24 hours.
    • Smaller ingestions can take 1-2 weeks
  • Symptoms: Listless, drunken walking, weakness, asymmetric pupils, rapid and uncontrolled eye movements, tremors, seizures, paralysis
  • Treatment: There is no antidote; treatment involves charcoal to absorb toxin left in the stomach, fluids, and other supportive care. Medications to reduce pressure in the brain, lessen tremors, and stop seizures may be necessary.

3. Vitamin overdoses

  • What do they do? Cause organ failure, most notably kidney failure.
  • Name to watch for: Cholecalciferol (Vitamin D3)
  • How long before my pet starts to show symptoms?
    • 12-36 hours
  • Symptoms: Vomiting, won’t eat, weakness, increased thirst and urination, bloody diarrhea, seizures
  • Treatment: There is no antidote; treatment involves charcoal to absorb toxin left in the stomach, fluids (a very specific type of intravenous fluid) and other supportive care.

4. Toxic gas (Zinc Phosphide)

  • Toxic mechanism: Zinc phosphide is converted to toxic phosphine gas in a moist and acidic environment (i.e. the stomach). This gas causes severe gastrointestinal, respiratory, cardiac and other organ damage.
  • Name to watch for: Zinc phosphide
  • How long before my pet starts to show symptoms?
    • 15 minutes to 4 hours
  • Symptoms: Vomiting (sometimes bloody), diarrhea, abdominal bloating and pain, rotten fishy breath, difficulty breathing, abnormal heart rhythms, fluid build-up in the lungs, drunken walking, weakness, tremors, seizures
  • Treatment: There is no antidote. Decontamination must be done in a well-ventilated (often outdoor) environment to reduce risk of human lung damage from toxic gas. Do NOT feed a small meal. A full stomach actually WORSENS toxicity from stomach acid production.

Hopefully, you never need to call regarding a potential toxic emergency, but just in case, here is contact info for an animal poison control center to keep handy.

Animal Poison Control ASPCA

Phone number: 888-426-4435



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