A dog with loose stool can worry any pet parent. Whether it’s a one-time mess or a recurring issue, soft or watery poop often signals that your dog’s digestive system is upset.
While it can sometimes be harmless, persistent loose stool can lead to dehydration or indicate an underlying illness that needs attention.
We outline the common reasons why a dog may have loose stool, what you can do at home, and when to seek veterinary help.
Dog Loose Stool: Why It Happens
Loose stool in dogs happens when the intestines aren’t properly absorbing water and nutrients, often due to irritation, infection, or diet changes. Common triggers include eating something unusual, food sensitivities, intestinal parasites, or stress.
Sometimes, it’s linked to more serious conditions like inflammatory bowel disease or organ dysfunction.
In mild cases, it may resolve with simple home care, but ongoing loose stool can signal deeper digestive or systemic problems that need veterinary attention.
Dog Loose Stool: Common Causes
Dietary Indiscretion
Dogs are natural scavengers, and one of the most common reasons for loose stool is when they eat something they shouldn’t — whether it’s garbage, spoiled food, table scraps, or something found on walks.
When a dog ingests food that is too rich, fatty, or contaminated, it irritates the gastrointestinal tract.
The intestines respond by speeding up movement to flush it out, leading to soft or watery stool. This can also be accompanied by gas, bloating, or mild vomiting.
If your dog’s appetite and energy remain normal, and the loose stool clears within 24 hours, it’s often a case of simple dietary upset.
However, if diarrhea persists or is accompanied by lethargy or vomiting, professional care is essential to rule out food poisoning or pancreatitis.
Read more: Dog Loose Stool at Night (Why it happens)
Sudden Diet Change
Even healthy, high-quality food can cause stomach issues if introduced too quickly. A dog’s digestive bacteria need time to adapt to new ingredients and nutrient ratios.
Switching brands, changing from kibble to raw food, or adding new treats without a gradual transition can all trigger loose stool.
The sudden influx of unfamiliar proteins, fats, or fiber confuses the gut flora, resulting in loose or frequent bowel movements.
To prevent this, always transition your dog’s food gradually over 7–10 days, mixing small portions of the new food with the old. This slow shift gives the digestive system time to adjust and minimizes stress on the intestines.
Intestinal Parasites
Parasites like roundworms, hookworms, whipworms, and Giardia are notorious for causing loose stool in dogs. These microscopic invaders damage the intestinal lining and disrupt absorption, leading to soft stool, mucus, or even visible worms in feces.
Puppies and dogs that spend time outdoors or at boarding facilities are at higher risk of contracting parasites from contaminated soil, water, or feces.
Along with diarrhea, symptoms may include weight loss, poor coat quality, and abdominal discomfort.
Because parasite infections are common yet easily treatable, stool testing (fecal exam) at your vet is vital whenever your dog develops persistent loose stool. Early detection prevents more serious complications and keeps your dog (and your household) safe.
Food Sensitivity
Chronic loose stool — especially if it occurs off and on — may point to a food intolerance or allergy. Dogs can develop sensitivities to certain proteins like chicken, beef, or dairy, as well as grains or additives in commercial food.
When your dog eats something that triggers inflammation, the immune system reacts in the gut.
This leads to loose, frequent stools, often with mucus or a strong odor. You may also notice itching, paw licking, or ear infections, which can accompany food allergies.
A veterinarian may recommend an elimination diet or limited-ingredient food to identify the cause.
Once the offending ingredient is removed, most dogs experience noticeable improvement in stool quality and overall health within weeks.
Bacterial or Viral Infections
Loose stool can also result from infections such as Salmonella, E. coli, or parvovirus. These infections disrupt normal intestinal balance and lead to inflammation that causes watery or bloody diarrhea.
Bacterial infections often come from contaminated water, raw food, or contact with other infected animals.
Parvovirus, on the other hand, is a serious and highly contagious disease, particularly dangerous for unvaccinated puppies.
Infectious diarrhea often comes on suddenly and may include vomiting, loss of appetite, fever, and weakness. Immediate veterinary attention is crucial, as untreated infections can quickly lead to dehydration and more severe illness.
Stress
Just like humans, dogs can experience “nervous stomachs.” Changes in environment, loud noises, traveling, new pets, or being left alone can all trigger stress-induced loose stool.
Stress hormones like cortisol affect intestinal motility, speeding up digestion and reducing nutrient absorption. The result is softer stool or temporary diarrhea, even if your dog’s diet hasn’t changed.
In these cases, stool often returns to normal once the stressor resolves. Offering a consistent routine, plenty of reassurance, and calming activities like gentle walks or chew toys can help soothe your dog’s nerves and digestive system alike.
Chronic Digestive Conditions
If your dog’s loose stool lasts longer than a few days or recurs regularly, chronic conditions like inflammatory bowel disease (IBD) or pancreatitis may be to blame.
IBD occurs when the immune system mistakenly attacks the intestinal lining, leading to inflammation and poor absorption. This results in soft stool, weight loss, and frequent bowel movements.
Pancreatitis, meanwhile, causes the pancreas to become inflamed, disrupting digestion and leading to loose stool, vomiting, and loss of appetite.
Both conditions require veterinary diagnosis and long-term management through diet modification, medications, and sometimes supplements to restore gut health.
Read more: Dog Loose Stool with No Other Symptoms (What it means)
Dog loose stool with blood
Loose stool with blood indicates irritation or inflammation in the digestive tract. Bright red blood usually comes from the lower intestines and is commonly caused by colitis, dietary indiscretion, parasites, stress, or sudden food changes.
Dark or tarry blood suggests bleeding higher up in the gastrointestinal tract and is more serious.
Even if the diarrhea seems mild, blood in the stool should always be monitored closely, and veterinary care is recommended if it continues beyond 24 hours or worsens.
Dog loose stool with mucus and blood
When loose stool contains both mucus and blood, it often points to large-bowel inflammation, such as colitis.
This can be triggered by stress, food intolerance, infections, parasites, or inflammatory bowel disease.
Dogs may strain, pass frequent small stools, or need to go urgently. While some cases resolve with dietary management, persistent or recurring mucus and blood require veterinary evaluation to rule out infections or chronic conditions.
Dog loose stool and vomiting
Loose stool combined with vomiting suggests a more significant gastrointestinal upset, such as food poisoning, viral or bacterial infection, pancreatitis, or toxin exposure.
This combination increases the risk of dehydration and electrolyte imbalance. Even if symptoms are mild at first, ongoing vomiting and diarrhea should not be treated at home for long.
Veterinary care is recommended if either symptom lasts more than 24 hours, worsens, or occurs in puppies or senior dogs.
Dog loose stool at night
Loose stool that occurs mainly at night is often linked to large-intestinal issues such as colitis or dietary sensitivity.
Stress, anxiety, late-night treats, or changes in feeding schedules can also trigger nighttime diarrhea.
Dogs with this issue may wake up urgently needing to go outside. If nighttime loose stools happen repeatedly or disrupt sleep, it’s a sign the digestive system is not fully recovering and should be evaluated.
Dog loose stool for a week
Loose stool lasting a full week is not normal and indicates an unresolved problem. Possible causes include parasites, chronic food intolerance, bacterial infection, inflammatory bowel disease, or ongoing stress.
Prolonged diarrhea can lead to weight loss, dehydration, and nutrient deficiencies. A dog with loose stool for a week should be seen by a veterinarian for diagnostic testing and targeted treatment rather than continued home management.
Puppy loose stool
Loose stool in puppies is common but should never be ignored because puppies dehydrate quickly. Causes include dietary changes, parasites, stress, teething, or viral and bacterial infections.
Puppies may still act playful at first, but diarrhea can worsen rapidly. If loose stools last more than 12–24 hours, contain blood, or are accompanied by vomiting, lethargy, or poor appetite, veterinary care is essential.
My dog has diarrhea but is acting fine
A dog can have diarrhea and still seem normal if the cause is mild, such as eating something unusual, stress, or a minor diet upset. However, “acting fine” does not always mean the issue is harmless.
Ongoing diarrhea can lead to dehydration and electrolyte imbalance. If diarrhea lasts more than 24–48 hours, becomes watery or bloody, or occurs in a puppy or senior dog, it should be checked by a veterinarian.
What to Do If Your Dog Has Loose Stool
If your dog has loose stool but seems otherwise healthy, you can often manage it at home for 24–48 hours. Start by withholding food for 12 hours (but never water) to give the digestive tract time to rest. Then, introduce a bland diet of boiled chicken and plain white rice in small portions.
Make sure your dog stays well hydrated. Offer fresh water and consider unflavored electrolyte solutions if the stool is very watery. You can also add a probiotic supplement to help restore healthy gut bacteria.
Keep your dog’s environment calm and avoid treats or rich foods during this recovery period. If the stool begins to firm up, gradually reintroduce regular food over several days.
However, if your dog’s loose stool continues beyond two days, becomes bloody, or is accompanied by vomiting or lethargy, don’t delay a vet visit — these may be signs of infection, parasites, or other serious conditions.
Read more: Dog Loose Stool and Vomiting (What it means)
When to Call or Visit Your Vet
You should contact your veterinarian right away if your dog’s loose stool is:
Lasting longer than 48 hours.
Accompanied by vomiting, blood, or mucus.
Causing your dog to refuse food or water.
Resulting in visible weight loss or dehydration.
Occurring in a puppy or senior dog.
Puppies and small breeds dehydrate quickly, so even mild diarrhea can become dangerous. Your vet will likely run a fecal exam, blood tests, and possibly imaging to identify the cause.
Prompt care ensures your dog recovers quickly and prevents minor digestive issues from developing into something more serious.
Read more: Dog Loose Stool and Drinking Lots of Water (When to be concerned)
Dog loose stool treatment
Treatment for loose stool depends on the cause, but mild cases are often managed with short-term dietary rest and supportive care.
Withholding food for 12 hours (for adult dogs), followed by a bland diet such as boiled chicken and rice, can help calm the digestive tract.
Ensuring adequate hydration is essential, as diarrhea quickly leads to fluid loss. If loose stools persist, contain blood, or recur frequently, veterinary treatment may be needed to address parasites, infections, food intolerances, or underlying disease. Treatment may include fluids, anti-parasitic medication, antibiotics, or prescription diets.
Key Takeaway
Loose stool in dogs can range from a simple dietary upset to a sign of infection or chronic illness. Monitor your dog’s stool, energy, and hydration closely.
If symptoms persist or worsen, your vet can help pinpoint the cause and recommend the right treatment plan.
With careful observation, a steady diet, and timely medical care, most dogs recover quickly — and you’ll both be back to cleaner walks and happier days in no time.