If your dog ate rat poop, the most likely outcome is nothing serious, especially from a single incident. But rat droppings can carry bacteria, parasites, and other pathogens that pose real health risks, so it’s worth knowing what to watch for in the hours and days that follow.
Why Rat Droppings Are a Problem
Rat feces can contain a surprising range of infectious organisms. The biggest concerns for dogs are leptospirosis, roundworms, and bacterial infections like Salmonella. Rats are also prolific carriers of diseases because they move through sewers, garbage, and soil, picking up pathogens along the way. A single rat dropping is a small exposure, but dogs that regularly scavenge or encounter rodent waste face a higher cumulative risk.
It’s also worth noting that rat poop and rat poison are different problems. If your dog ate droppings near a bait station, check carefully for any signs that poison was also consumed. Colored pellets, waxy blocks, or unusual-looking material mixed in with the droppings warrants an immediate call to your vet.
Leptospirosis
This is the most serious infection dogs can pick up from rat waste. Leptospirosis is a bacterial disease spread through the urine of infected animals, and rats are one of the primary carriers. Dogs get infected when the bacteria enters through the mouth, nose, eyes, or broken skin. Eating rat droppings contaminated with urine is a direct route of exposure.
Early signs include loss of appetite, vomiting, diarrhea, unusual tiredness, and changes in how much your dog urinates (either more or less than normal). These symptoms can appear anywhere from a few days to a couple of weeks after exposure. Left untreated, leptospirosis can damage the kidneys and liver and become life-threatening. A leptospirosis vaccine is available and is one of the most effective ways to reduce this risk, particularly for dogs that spend time outdoors or in areas with known rodent activity.
Roundworms and Other Parasites
Dogs can pick up roundworm infections by swallowing parasite eggs found in contaminated feces or soil. Rats themselves can harbor roundworms, so eating their droppings is a recognized transmission route. According to Cornell University’s College of Veterinary Medicine, dogs become infected either by ingesting roundworm eggs from contaminated material or by eating an infected rodent directly.
Roundworm infections often don’t cause obvious symptoms in adult dogs right away. Over time, a heavy worm burden can lead to a pot-bellied appearance, weight loss, dull coat, and diarrhea. Puppies are more vulnerable and can become seriously ill. The good news is that a standard fecal exam at your vet’s office can detect roundworm eggs, and treatment with a deworming medication is straightforward.
Bacterial Infections
Rat droppings can harbor Salmonella and Campylobacter, two bacteria that cause gastrointestinal illness. In dogs, Salmonella typically causes fever, vomiting, abdominal pain, loss of appetite, and diarrhea. It’s considered a moderate illness: uncomfortable and sometimes incapacitating, but not usually life-threatening in otherwise healthy dogs.
Campylobacter tends to be milder and more self-limiting. Puppies under six months are the most susceptible, and symptoms usually involve watery or mucus-streaked diarrhea lasting 5 to 15 days, sometimes with vomiting and fever. Adult dogs with healthy immune systems often fight off Campylobacter without needing treatment.
Hantavirus and Toxoplasmosis
Two infections that sometimes worry dog owners turn out to be less of a concern than you might expect. Hantavirus, which can be serious in humans, does not cause illness in dogs. According to the Washington State Department of Health, dogs can technically become infected with hantavirus when exposed to rodent waste, but they don’t get sick or show any symptoms. The indirect risk is that dogs could bring infected rodents or contaminated material into your home, potentially exposing you.
Toxoplasmosis is primarily a cat-associated disease. Dogs don’t produce the infectious form of the parasite in their own feces the way cats do. While dogs can technically encounter Toxoplasma through contaminated material, rat droppings are not a significant transmission route for this parasite in dogs.
Symptoms to Watch For
After your dog eats rat droppings, keep a close eye on them for the next one to two weeks. Most infections have an incubation period, so symptoms may not appear immediately. Here’s what to look for:
- Vomiting or diarrhea that lasts more than 24 hours, or diarrhea that contains blood or mucus
- Loss of appetite or refusal to eat for more than a day
- Lethargy or unusual tiredness that doesn’t improve with rest
- Changes in urination, either producing much more or much less urine than normal
- Fever, which you may notice as warm ears, a dry nose, or general listlessness
A single episode of vomiting or loose stool right after eating something unusual isn’t necessarily alarming. It’s persistent or worsening symptoms, or any combination of the signs above, that should prompt a vet visit.
What Your Vet Can Do
If your dog develops symptoms after eating rat droppings, your vet will likely start with a fecal exam to check for parasites like roundworms. Blood work and urine tests can screen for leptospirosis and assess kidney and liver function. More specialized testing, such as PCR (a DNA-based test that identifies specific pathogens), is available when a particular infection is suspected.
For a dog that ate rat poop once, shows no symptoms, and is otherwise healthy and up to date on vaccines, most vets won’t recommend aggressive testing. They may suggest monitoring at home and bringing in a stool sample if symptoms develop. If your dog is a puppy, elderly, or has a compromised immune system, your vet may take a more proactive approach.
Reducing the Risk Going Forward
Dogs eat gross things. You can’t always prevent it, but you can reduce the odds. Keep your yard free of debris, woodpiles, and food sources that attract rats. When walking your dog, steer them away from areas near dumpsters, alleyways, or storm drains where rodent activity is high. Teaching a reliable “leave it” command is one of the most practical tools for this exact scenario.
Talk to your vet about the leptospirosis vaccine if your dog isn’t already vaccinated. It’s not part of every standard vaccine protocol, but it’s recommended for dogs with higher exposure risk, including those in urban areas, near bodies of water, or in regions with large rodent populations. Keeping your dog on a regular deworming schedule also provides a safety net against parasitic infections picked up from scavenging.