Rat Poison Ingestion: Superwarfarin Bleeding, Bromethalin Neurotoxicity, and Zinc Phosphide Gas¶

Discovering that a toddler, adult, or household pet has chewed or swallowed rodenticide ("rat poison" or "mouse bait") triggers immediate panic, yet the medical treatment required depends entirely on which of the four completely different chemical classes of rodenticide was inside the bait station. For decades, almost all household rat poisons were long-acting anticoagulant "superwarfarins" (such as brodifacoum or bromadiolone) that block vitamin K clotting factors and are completely reversible with oral or intravenous Vitamin K1 (phytonadione). However, regulatory changes by the United States Environmental Protection Agency (EPA) and international pesticide authorities have shifted millions of consumer bait blocks over to Bromethalin (a potent mitochondrial neurotoxin that causes lethal brain swelling with no antidote), Cholecalciferol (massive-dose Vitamin D3 that causes life-threatening hypercalcemia and kidney calcifications), and agricultural/mole pellets containing Zinc Phosphide or Aluminum Phosphide (which react violently with stomach acid and water to release deadly phosphine gas inside the digestive tract).

Because green, blue-green, red, or tan bait blocks, pellets, and grain packs from all four chemical classes look virtually identical to the naked eye, treating every rat poison ingestion as a "blood thinner" is a potentially fatal mistake. If anyone has swallowed or touched rodenticide, call your local emergency number (911 in the United States and Canada, 112 across the European Union, 999 in the United Kingdom) via our emergency numbers directory or your regional poison center right away, and review poisoning first aid, severe bleeding control, and seizure first aid.

Do this now¶

1. Call Poison Control or emergency services immediately and find the bait box label: Call 911 (US/Canada), 112 (EU), or 999 (UK) if the person was exposed to zinc phosphide / aluminum phosphide, took an intentional overdose, or has any symptoms (vomiting, headache, confusion, tremors, seizures, or bleeding). For accidental child exploratory tastes, call Poison Control (1-800-222-1222 in the US) immediately while locating the exact cardboard box, plastic bait station, or EPA Registration Number to read the "Active Ingredient" line on the front label.
2. STOP: Do NOT give water, milk, or fluids until you rule out Zinc Phosphide: If the bait is a gray/black pellet, grain, or powder used for moles, gophers, or farm rats (Zinc Phosphide or Aluminum Phosphide), or if the person's breath or vomit smells like rotten fish or garlic, DO NOT give water, milk, or any liquid, and DO NOT induce vomiting. Water and stomach acid react with zinc phosphide to release lethal phosphine gas (PH3), which can poison both the patient and anyone breathing near their mouth or vomit.
3. Wipe out the mouth and wash hands and face with soap and water: Using a damp cloth (or dry cloth if zinc phosphide is suspected), sweep any unswallowed crumbs, pellets, or colored wax fragments out of a child's mouth and save them in a sealed plastic bag for hospital identification. Wash the person's hands and face thoroughly with soap and water.
4. Never rely on the color or shape of the bait block to guess the chemical: Green, blue, turquoise, pink, or tan wax blocks and pellets are dyed strictly to show that they are non-food pesticides and to mark rodent droppings. A green block of D-Con, Tomcat, or Victor can contain brodifacoum (anticoagulant), bromethalin (neurotoxin), or cholecalciferol (Vitamin D3) depending on the exact product line and year of purchase.
5. Do not give over-the-counter Vitamin K supplements or induce vomiting at home: Over-the-counter pharmacy bottles of Vitamin K often contain Vitamin K2 (menaquinone) or microgram doses (100 mcg) that are 100 to 500 times too weak to reverse superwarfarin poisoning (which requires prescription-strength milligram doses of Vitamin K1 [phytonadione]), and Vitamin K does nothing at all for bromethalin, cholecalciferol, or zinc phosphide.
6. Know the delayed symptom window (24 hours to 7 days): Never assume a person or child is safe just because they feel completely normal on Day 1. Superwarfarins take 36 to 72 hours before clotting factors drop and bleeding starts; cholecalciferol takes 24 to 72 hours to spike blood calcium; and low-to-moderate bromethalin exposures can take 1 to 4 days to trigger progressive brain swelling and ataxia.

Decision tree: Identifying and triaging the four classes of rodenticide¶

flowchart TD
    Start["Suspected Rodenticide (Rat, Mouse, Mole, or Gopher Poison) Ingestion"] --> ReadLabel["Check Bait Box Label, EPA Reg. No., or Physical Clues (Odor / Pellet vs Wax Block)"]

    ReadLabel --> ClassSplit{"What Is the Active Ingredient on the Label?"}

    ClassSplit -->|1. Long-Acting Anticoagulant 'Superwarfarin' (Brodifacoum, Bromadiolone, Difenacoum, Difethialone, Chlorophacinone)| SuperWarfarin["Mechanism: Inhibits Vitamin K Epoxide Reductase (Factors II, VII, IX, X); Onset Delayed 36-72 Hours; Half-Life Months"]
    ClassSplit -->|2. Bromethalin (Most Modern US Consumer Mouse/Rat Blocks)| Bromethalin["Mechanism: Uncouples Brain Mitochondrial Oxidative Phosphorylation -> Intramyelinic Cerebral Edema; NO ANTIDOTE"]
    ClassSplit -->|3. Cholecalciferol (Vitamin D3 Bait)| VitD3["Mechanism: Massive Vitamin D3 Overdose -> Severe Hypercalcemia, Acute Kidney Failure, Cardiac Calcification (Onset 24-72h)"]
    ClassSplit -->|4. Zinc Phosphide / Aluminum Phosphide (Rotten Fish/Garlic Odor Pellets) OR Strychnine| Phosphide["Mechanism: Stomach Acid + Water -> Lethal Phosphine Gas (PH3) -> Cytochrome C Oxidase Blockade, Shock, Pulmonary Edema"]

    SuperWarfarin --> SW_Care["Triage: Accidental Single Taste in Child (< 1 mg) Often Safe to Track; Large/Intentional Ingestion -> Activated Charcoal (if <1-2h), Check Baseline & 48-72h PT/INR; Treat Only Elevated INR/Bleeding with High-Dose Oral/IV Vitamin K1 (Phytonadione) for Weeks to Months + PCC/FFP if Active Bleeding"]

    Bromethalin --> Brom_Care["Triage: Early Multi-Dose Activated Charcoal + Whole-Bowel Irrigation for Large Ingestions; Monitor in ICU for Headache, Tremors, Ataxia, Delirium, Seizures, and Raised Intracranial Pressure (Hypertonic Saline / Mannitol)"]

    VitD3 --> VitD_Care["Triage: Activated Charcoal; Serial Serum Calcium, Ionized Calcium, Phosphorus, and Creatinine at 24h, 48h, 72h; Treat Hypercalcemia with Aggressive IV 0.9% Normal Saline, Calcitonin, IV Bisphosphonates (Pamidronate/Zoledronic Acid), and Corticosteroids"]

    Phosphide --> Phos_Care["Triage: DO NOT GIVE WATER; Ventilate Area; Seal Vomit; Suppress Stomach Acid (PPI + Sodium Bicarbonate); Oil-Based Gastric Lavage (Coconut/Mineral Oil); ICU Vasopressors, IV Magnesium Sulfate, and N-Acetylcysteine"]

Master Identification Table: The Six Chemical Classes of Rodenticide¶

Because brand names like d-CON, Tomcat, Victor, Contrac, Havoc, Talon, Just One Bite, Rampage, and Terad3 reuse their brand logos across multiple chemical formulas, always match the exact chemical name under "Active Ingredients" on the package label:

Class 1 Deep Dive: Superwarfarin Anticoagulants (Brodifacoum, Bromadiolone, Difenacoum)¶

1. Why "Superwarfarins" Are 100 Times More Potent and Last for Months¶

Standard medical warfarin (Coumadin) has a plasma half-life of roughly 35 to 40 hours. When rats evolved genetic resistance to ordinary warfarin in the 1970s, chemists added a bulky, highly lipophilic (fat-soluble) phenyl-ring side chain to the coumarin molecule, creating second-generation 4-hydroxycoumarin "superwarfarins" (brodifacoum, bromadiolone, difenacoum, difethialone, and flocoumafen) and long-acting indandiones (chlorophacinone and diphacinone).

• Mechanism of Action: Vitamin K is required by the liver enzyme gamma-glutamyl carboxylase to activate four essential blood-clotting proteins: Factor II (Prothrombin), Factor VII, Factor IX, and Factor X (plus regulatory Proteins C and S). During this activation, active reduced Vitamin K hydroquinone is oxidized into inactive Vitamin K 2,3-epoxide, which must then be recycled back into active Vitamin K by the enzyme Vitamin K Epoxide Reductase (VKORC1).
• Irreversible Hepatic Storage: Superwarfarins bind to VKORC1 with 100-fold greater affinity than medical warfarin and concentrate inside liver fat stores with an elimination half-life in humans of 16 to 69 days (extending total biological anticoagulation to 1 to 9+ months after a single large overdose).
• Why the INR Is Completely Normal for the First 24 to 36 Hours: Superwarfarins do not destroy clotting factors that are already circulating in the bloodstream; they only stop the liver from making new ones. Because Factor VII has the shortest half-life (6 hours), followed by Factor IX (24 hours), Factor X (36 hours), and Factor II (60 hours), a blood test (Prothrombin Time [PT] and International Normalized Ratio [INR]) drawn in the emergency room 4 or 12 hours after swallowing brodifacoum will be 100 percent normal (INR 1.0). The INR only begins rising at 24 to 36 hours and peaks at 48 to 72 hours, which is when spontaneous bleeding begins.

2. Pediatric Single-Taste Triage vs. Intentional Overdose Protocol¶

1. Unintentional Exploratory Taste in a Young Child (< 1 mg of Superwarfarin):
2. Household superwarfarin baits are extremely dilute (0.005% brodifacoum, meaning 1 gram of bait contains only 0.05 mg of brodifacoum).
3. Extensive poison center studies prove that a healthy toddler who accidentally mouths or swallows a few crumbs or less than a single pellet/mouthful (less than 1 mg of active brodifacoum, which equals 20 grams [0.7 ounces] of 0.005% bait) almost never develops clinically significant coagulopathy or bleeding, and usually does not even require routine blood draws unless they swallow a large quantity, have repeated exposures, or develop bruising. Always let Poison Control calculate the exact weight-based dose.
4. Large, Intentional, or Repeated Ingestion (Hospital Evaluation Required):
5. Never Give Empiric Prophylactic Vitamin K1 Before Checking the 48-Hour INR: If a doctor gives Vitamin K1 on Day 1 right after an ingestion, it will mask the 48-hour INR blood test, making it impossible to know whether the patient actually ingested a toxic dose that will require months of treatment once the single dose of Vitamin K wears off.
6. Instead, in an asymptomatic patient, physicians administer Activated Charcoal (if within 1 to 2 hours), draw a baseline PT/INR, and repeat the PT/INR at 48 hours and 72 hours post-ingestion. If the INR is still completely normal at 48 and 72 hours without Vitamin K having been given, significant superwarfarin poisoning is ruled out.
7. Treating Elevated INR (> 2.0 to 4.0) or Active Bleeding:
8. Active Life-Threatening Hemorrhage (intracranial bleeding, gastrointestinal bleeding, hematuria, or shock): Immediately infuse 4-Factor Prothrombin Complex Concentrate (4F-PCC / Kcentra at 25 to 50 Units/kg IV) (or Fresh Frozen Plasma [FFP at 15 to 20 mL/kg] if PCC is unavailable) to instantly replace Factors II, VII, IX, and X, alongside 10 to 20 mg of Intravenous Vitamin K1 (Phytonadione) infused slowly at no more than 1 mg/minute (to avoid rare anaphylactoid reactions).
9. Long-Term High-Dose Oral Vitamin K1 Maintenance: Because the superwarfarin stays in the liver for months while Vitamin K1 has a short 6-hour duration, patients with superwarfarin coagulopathy require massive prescription doses of Oral Vitamin K1 (Phytonadione), typically 50 mg to 200+ mg per day divided every 6 to 8 hours, continuously for 4 weeks to 6+ months, guided by serial INR checks and serum brodifacoum levels. (Important: Only Vitamin K1 [phytonadione] works; Vitamin K3 [menadione] is completely ineffective and causes hemolytic anemia).

Class 2 Deep Dive: Bromethalin (The Modern Neurotoxic Cerebral Edema Bait)¶

Because the US EPA restricted consumer retail sales of second-generation superwarfarins, Bromethalin is now the active ingredient inside the majority of mouse and rat blocks sold in supermarkets and hardware stores across North America.

• How Bromethalin Poisons the Brain: Once absorbed from the gut, bromethalin (a highly lipophilic diphenylamine) is metabolized by liver cytochrome P450 enzymes into desmethylbromethalin, an even more potent toxin that crosses the blood-brain barrier and uncouples mitochondrial oxidative phosphorylation across the brain and spinal cord. Deprived of cellular ATP, the Na+/K+-ATPase pumps along nerve axons fail, causing sodium and water to flood inside the myelin sheaths wrapping the white matter tracts (intramyelinic vacuolization and spongy cerebral edema).
• Clinical Presentation:
• Small Accidental Pediatric Taste: Because consumer bromethalin bait is 0.01% (0.1 mg of bromethalin per gram of bait), an accidental single crumb taste by a child rarely reaches the human neurotoxic threshold, though every exposure must be evaluated by Poison Control.
• Large Intentional or Pet Ingestion: Causes severe throbbing headache, intractable vomiting, hyperthermia (fever), coarse muscle tremors, hyperreflexia, myoclonus, cerebellar ataxia, delirium, generalized status epilepticus, raised intracranial pressure, brainstem herniation, and death.
• Hospital Management (No Antidote Exists):
• Vitamin K1 is completely useless for bromethalin and must not be relied upon.
• Because bromethalin undergoes extensive enterohepatic recirculation (excreted in bile and reabsorbed from the intestine) with a half-life of 6 days, hospital teams administer Multi-Dose Activated Charcoal (MDAC) and/or Whole-Bowel Irrigation early to strip unabsorbed and recirculating toxin from the gut, followed by aggressive ICU management of seizures (benzodiazepines, propofol, or barbiturates), MRI monitoring of white matter cerebral edema, and osmotherapy (3% Hypertonic Saline or Mannitol) for elevated intracranial pressure.

Class 3 Deep Dive: Cholecalciferol (Massive Vitamin D3 Hypercalcemia)¶

Cholecalciferol rodenticides (0.075% Vitamin D3, equal to 30,000 IU of Vitamin D3 per gram of bait) kill rodents by inducing lethal hypercalcemia (sky-high blood calcium) and calcifying their kidneys, heart, and aorta:

• Delayed Onset (24 to 72 Hours): After ingestion, the liver converts cholecalciferol into 25-hydroxyvitamin D (25-OH-D), which floods vitamin D receptors, pulling massive amounts of calcium and phosphorus out of the intestines and stripping calcium out of the bones.
• Clinical Signs: Extreme thirst, heavy urination, severe nausea, vomiting, abdominal pain, constipation, high blood pressure, lethargy, confusion, a shortened QTc interval and Osborn J-waves on the ECG, and acute renal failure (nephrocalcinosis).
• Hospital Treatment Protocol:
• Early Activated Charcoal (or cholestyramine to bind fat-soluble vitamin D in the gut) and serial serum total calcium, ionized calcium, phosphorus, BUN/creatinine, and 25-OH-Vitamin D levels at baseline, 24, 48, and 72 hours.
• Aggressive Intravenous 0.9% Normal Saline Hydration (200 to 300 mL/hour) to restore intravascular volume and promote urinary calcium excretion (calciuresis), adding furosemide only after volume depletion is corrected.
• Subcutaneous/IM Calcitonin (4 to 8 IU/kg every 6 to 12 hours) for rapid calcium lowering within 4 to 6 hours, paired with Intravenous Bisphosphonates (Zoledronic Acid 4 mg IV or Pamidronate 60 to 90 mg IV) to permanently block osteoclast bone resorption over 48 hours to 3 weeks, plus Oral/IV Glucocorticoids (Prednisone or Hydrocortisone) to inhibit 1-alpha-hydroxylase activation and intestinal calcium absorption.

Class 4 Deep Dive: Zinc Phosphide and Aluminum Phosphide (Lethal Phosphine Gas)¶

Used in agricultural grain baits, gopher/mole pellets (Moletox, ZP Bait), and grain fumigant tablets (Celphos, Phostoxin), Zinc Phosphide (Zn3P2) and Aluminum Phosphide (AlP) are among the most rapidly lethal poisons on Earth:

• The Chemical Reaction in the Stomach: Solid Zn3P2 reacts with 6 HCl (stomach hydrochloric acid) and water (H2O) to form 3 ZnCl2 and 2 PH3 (lethal phosphine gas).
• Why Water Is Strictly Forbidden: Any water or acidic liquid swallowed by the patient, or used by an uninformed clinician for standard saline gastric lavage, accelerates hydrolysis and releases a sudden, fatal cloud of phosphine gas (PH3).
• Hospital Rescue Bundle for Zinc/Aluminum Phosphide:
• Personal Protective Equipment (PPE) & Ventilation: Treat the patient in a well-ventilated negative-pressure room; seal all vomit and gastric contents immediately so staff do not inhale phosphine gas.
• Immediate Gastric Acid Suppression: Administer Intravenous Proton Pump Inhibitors (Pantoprazole 80 mg IV) and Oral/IV Sodium Bicarbonate immediately to raise gastric pH above 6.0, stopping hydrochloric acid from converting remaining zinc phosphide into phosphine gas.
• Oil-Based Gastric Decontamination (NEVER Water-Based): If performing gastric lavage within 1 to 2 hours, use medicinal liquid paraffin, mineral oil, or coconut oil (along with oil-suspended activated charcoal or sodium bicarbonate) to coat the zinc phosphide particles and prevent water contact while aspirating the stomach.
• ICU Mitochondrial and Myocardial Support: Infuse Intravenous Magnesium Sulfate (stabilizes myocardial membranes and reduces free radical lipid peroxidation), Intravenous N-Acetylcysteine (NAC) (replenishes glutathione against oxidative hepatic injury), High-Dose Insulin Euglycemic Therapy (HIET), Norepinephrine, and Early VA-ECMO for refractory toxic myocarditis and cardiogenic shock.

Regional emergency numbers and agency protocols¶

Frequently asked questions¶

Why can't a doctor just give Vitamin K for every rat poison ingestion?¶

Vitamin K1 (phytonadione) only works for anticoagulant ("superwarfarin") rat poisons like brodifacoum or bromadiolone. Because modern hardware-store brands like d-CON, Tomcat, and Victor now sell millions of green bait blocks made with Bromethalin (a brain-swelling neurotoxin with no antidote) or Cholecalciferol (massive-dose Vitamin D3 that causes fatal calcium spikes), giving Vitamin K for those poisons does nothing at all and creates a false sense of security. Even for true superwarfarin ingestions, doctors wait to check a 48-hour INR blood test before starting Vitamin K in asymptomatic patients so they don't mask whether the patient actually absorbed a toxic dose.

How can I tell whether a green rat poison block is a superwarfarin blood thinner, Bromethalin, or Vitamin D3?¶

You CANNOT tell by looking at the color or shape of the block. Manufacturers dye all three types of rodenticide green, blue-green, pink, or tan using the exact same food dyes and mold shapes. The only reliable way to identify the poison is to read the "Active Ingredient" line and the EPA Registration Number printed on the front of the cardboard box or stamped onto the plastic bait station, and read those exact words to Poison Control (1-800-222-1222 in the US) or the emergency room physician.

Why is it dangerous to give water to someone who swallowed zinc phosphide mole or rat pellets?¶

When zinc phosphide or aluminum phosphide pellets come into contact with water and stomach acid, an immediate chemical reaction occurs that converts the solid powder into lethal phosphine gas inside the stomach. Giving water speeds up this reaction, releasing a cloud of phosphine gas that destroys the patient's heart, lungs, and liver and can also be exhaled or vomited out to poison rescuers and emergency room staff. Instead, hospitals neutralize stomach acid with intravenous proton pump inhibitors and sodium bicarbonate and use coconut oil or mineral oil rather than water for stomach decontamination.

If someone swallows a superwarfarin rat poison like brodifacoum and their emergency room blood test (INR) is completely normal 6 hours later, are they out of danger?¶

No. Superwarfarins do not destroy the blood-clotting proteins that are already floating in your bloodstream; they only block your liver from making new clotting proteins. Because it takes 24 to 48 hours for your body to use up its existing supply of Factor VII and Factor II, a blood test drawn 6 or 12 hours after swallowing rat poison will always look 100 percent normal, even after a lethal dose. To rule out superwarfarin poisoning, the PT/INR blood test must be repeated at 48 hours and 72 hours after the ingestion.

Why do patients poisoned by superwarfarin rat bait have to take huge doses of prescription Vitamin K1 pills every day for months?¶

Unlike medical warfarin (which clears from the body in a few days), second-generation "superwarfarins" like brodifacoum are extremely fat-soluble and stay trapped inside the liver for 2 to 9 months, continuously blocking the enzyme that recycles Vitamin K. Because each dose of oral Vitamin K1 only allows the liver to make clotting factors for about 6 to 8 hours before being used up, patients with severe superwarfarin poisoning must take massive prescription doses (50 mg to 200 mg per day, divided every 6 to 8 hours) every single day for weeks or months until the poison is finally eliminated from the liver.

Related guides¶

• Poisoning first aid and poison control triage
• Severe bleeding control and hemorrhagic shock
• Cyanide, hydrogen sulfide, and industrial gas inhalation first aid
• Organophosphate pesticide, nerve agent, and insecticide poisoning
• Seizure first aid and safety

Sources and official guidance¶

• American Association of Poison Control Centers (AAPCC): Evidence-Based Consensus Guideline for Out-of-Hospital Management of Long-Acting Anticoagulant Rodenticide Ingestions (Clinical Toxicology).
• United States Environmental Protection Agency (EPA): Recognition and Management of Pesticide Poisonings (6^th Edition): Anticoagulant Rodenticides, Bromethalin, Cholecalciferol, and Zinc Phosphide.
• American College of Medical Toxicology (ACMT): Clinical Management of Superwarfarin Coagulopathy, Synthetic Cannabinoid Brodifacoum Outbreaks, and Non-Anticoagulant Rodenticides.
• National Poisons Information Service (NPIS, United Kingdom): TOXBASE Clinical Protocols for Superwarfarin, Bromethalin, Cholecalciferol, and Metal Phosphide Poisoning.
• World Health Organization (WHO): International Programme on Chemical Safety (IPCS): Health and Safety Guides for Brodifacoum, Bromethalin, and Phosphine / Metal Phosphides.

This guide is for informational purposes and does not replace professional medical evaluation, Poison Control consultation, or veterinary/hospital intensive care. Because rodenticide poisonings can cause delayed internal hemorrhage, cerebral edema, or toxic gas release, we strongly recommend taking an accredited hands-on first aid and CPR course through the International Federation of Red Cross and Red Crescent Societies (IFRC), your national Red Cross society, St John Ambulance, or a certified local provider.