Bromadiolone can kill a dog, but the lethal dose depends on the dog’s size and how much was consumed. The median lethal dose (LD50) for bromadiolone in dogs is 6 to 15 mg per kilogram of body weight, which places it in the middle range of anticoagulant rodenticides. With prompt veterinary treatment, most dogs survive. One study of 21 dogs treated for anticoagulant rodenticide poisoning found an 83% survival rate.
How Bromadiolone Poisons Dogs
Bromadiolone is a second-generation anticoagulant rodenticide, meaning it was designed to kill rodents with a single feeding. It works by blocking an enzyme the liver needs to recycle vitamin K. Without functional vitamin K, the body stops producing four essential clotting factors. Over the following days, the dog’s blood gradually loses its ability to clot, and uncontrolled internal bleeding begins.
This delayed mechanism is what makes anticoagulant rodenticides so dangerous and so deceptive. Your dog won’t show any signs of distress right after eating it. The poison works silently as clotting factors already circulating in the blood are used up and not replaced.
How Much Is Dangerous
Most commercial bromadiolone bait products contain 0.005% active ingredient (50 parts per million). That means a 1-ounce block of bait contains roughly 1.4 mg of bromadiolone. For a 20-pound (9 kg) dog, the lethal range would be somewhere around 54 to 135 mg of pure bromadiolone, which translates to a large number of bait blocks. A small dog, however, could reach a dangerous dose much faster.
The important thing to understand is that you don’t need to hit the lethal dose to cause serious harm. Even sub-lethal amounts can trigger bleeding episodes that require emergency intervention. If you know or suspect your dog ate any amount of bromadiolone bait, treat it as an emergency regardless of how much you think was consumed.
Can Dogs Be Poisoned by Eating a Dead Rat?
Yes, secondary poisoning (sometimes called relay toxicity) is a real concern. If your dog eats a rat or mouse that recently consumed bromadiolone, some of the poison transfers to your dog. Second-generation anticoagulants like bromadiolone are more concentrated and persistent in tissues than older products like warfarin, which makes relay toxicity more plausible. A single poisoned rodent is unlikely to contain enough bromadiolone to kill a large dog, but smaller dogs and dogs that eat multiple rodents face genuine risk.
Symptoms and When They Appear
Signs of bromadiolone poisoning typically appear 2 to 5 days after ingestion, once the existing clotting factors in the bloodstream have been depleted. This delay catches many owners off guard, especially if they didn’t witness the initial exposure.
Early symptoms are often vague: loss of appetite, tiredness, and general weakness. As the poisoning progresses, bleeding becomes apparent in various forms:
- Nosebleeds that start without any injury
- Pale gums from internal blood loss
- Dark, tarry stools (digested blood in the intestines)
- Blood in urine
- Coughing or difficulty breathing from bleeding into the chest cavity or lungs
- Bruising or small red spots visible on the skin or gums
Less common signs depend on where the bleeding occurs. Some dogs develop a sudden limp from bleeding into a joint, lose coordination, or have seizures if bleeding happens near the brain. In severe cases, a dog can collapse from blood loss with little warning.
What Happens at the Vet
If you bring your dog in shortly after ingestion (within about two hours), the vet will likely induce vomiting and administer activated charcoal to reduce absorption. This early decontamination can prevent the poisoning from ever reaching dangerous levels.
The core treatment is vitamin K1, which directly counteracts what bromadiolone does by restoring the body’s ability to produce clotting factors. Treatment typically lasts up to 4 weeks for second-generation anticoagulants like bromadiolone. This extended course is necessary because bromadiolone lingers in the body. Research in dogs found bromadiolone has a terminal half-life of about 30 days, meaning it takes roughly a month for half the absorbed poison to be eliminated. The substance recirculates between the liver and intestines, which prolongs its effects.
Dogs that arrive already bleeding may need blood transfusions or plasma to replace lost clotting factors while the vitamin K1 takes effect (it generally needs 6 to 12 hours to start working). After the treatment course ends, vets typically run a clotting test 48 to 72 hours later to confirm the dog’s blood is clotting normally before declaring the dog safe.
Survival and Long-Term Outlook
Dogs treated before severe bleeding develops have an excellent prognosis. Even among dogs that arrived at the vet already symptomatic, the 83% survival rate in published case series is encouraging, and that figure includes dogs with advanced poisoning. The dogs that don’t survive are generally those with catastrophic internal bleeding, particularly into the chest or brain, before treatment begins.
Dogs that recover fully from bromadiolone poisoning typically have no lasting organ damage. The key variable is time. A dog treated within hours of ingestion, before any clotting problems develop, will almost certainly survive with no complications. A dog that goes days without treatment while internal bleeding worsens faces a much more uncertain outcome.
How Bromadiolone Compares to Other Rat Poisons
Not all rodenticides are equally dangerous to dogs. Bromadiolone sits in the middle of the pack among anticoagulant products. For comparison, brodifacoum (the active ingredient in many d-CON products) has a lethal dose of just 0.2 to 4 mg/kg, making it 3 to 30 times more toxic than bromadiolone on a weight basis. Brodifacoum also persists far longer in the body, with a half-life of 200 to 330 days compared to bromadiolone’s 30 days. On the other end, older first-generation products like warfarin require much larger doses (20 to 300 mg/kg) and typically need repeated exposures to cause lethal poisoning.
If your dog ate rat poison and you can identify the product, bring the packaging to the vet. The active ingredient determines how aggressive treatment needs to be and how long it will last. Bromadiolone’s 4-week treatment window is shorter than what brodifacoum requires, which can mean fewer vet visits and a faster return to normal.