Finding loose or runny stools in your dog's usual spot can be worrying, especially when it happens suddenly or carries on for more than a day. Soft stools and diarrhoea are among the most common health issues in dogs. Most cases settle quickly with the right care, but they're not something to ignore completely, as they can signal anything from a simple dietary upset to a problem that needs veterinary attention.
Is Runny Poop the Same as Diarrhoea?
Yes. Diarrhoea simply means your dog is passing loose or liquid stools more often than usual, or in larger amounts than normal. It happens when the digestive system can't properly absorb water from food as it moves through the intestines, so you see watery or soft stools instead of the firm, well-formed ones you'd normally expect.
Diarrhoea is a symptom rather than a disease, so watching your dog's overall behaviour matters as much as looking at their stools.
The Four Types of Diarrhoea
Vets recognise four main types, which can help you describe what you're seeing:
- Osmotic: water is drawn into the intestines, often after something rich, fatty or hard to digest. Usually improves when your dog hasn't eaten for a while.
- Secretory: excess secretions caused by bacterial toxins or viruses. Very watery, and doesn't improve even when your dog isn't eating.
- Exudative: the intestinal lining is damaged, often producing stools with mucus or blood.
- Rapid transit: the intestines contract more intensely than normal, pushing contents through too quickly for water to be absorbed.
When to contact your vet about diarrhoea or loose stools
Mild, short-term soft stools
A single episode or soft stools lasting less than 24 hours in an adult dog who is otherwise bright, active and eating normally. Careful home care with close monitoring may be appropriate.
Persistent or concerning signs
Diarrhoea lasting more than 24 hours, mucus in the stools, loss of appetite, recurring episodes, or a dog who seems generally unwell. Puppies, senior dogs and dogs with existing health conditions need advice sooner.
Severe symptoms needing immediate care
Blood in the stools, persistent vomiting, severe lethargy or collapse, signs of dehydration, or suspected toxin or foreign body ingestion. Seek veterinary attention straight away.
Common Causes of Runny Poop and Diarrhoea
Dietary Indiscretion
The most frequent cause of sudden loose stools is your dog eating something they shouldn't have: raiding the bin, scavenging on a walk, counter-surfing or being given fatty human food. These episodes often settle on their own if your dog stays bright, active and keeps their normal appetite and thirst.
Too-Quick Food Changes
Switching food too quickly is one of the most preventable causes of digestive upset. Your dog's gut bacteria need time to adjust to new proteins, fibre sources and nutrient profiles, so a gradual transition over 7-10 days (see the schedule below) avoids most problems.
Stress and Anxiety
Moving house, changes in routine, new family members, thunderstorms, vet visits or separation anxiety can all trigger loose stools in sensitive dogs. Anxiety disorders in dogs can flood the body with cortisol, which disrupts the balance of gut bacteria and makes the gut wall less effective at controlling what passes through. If your dog also seems uncomfortable or unsettled, our guide on how to know if your dog is in pain may help.
Food Sensitivities and Ingredients
Adverse food reactions affect a notable portion of dogs, with numbers rising in dogs who already have allergic conditions. True food allergies are less common than many owners think, though. When they do occur, they most often involve proteins such as chicken or beef, or dairy, and usually cause skin problems alongside digestive symptoms.
Other common triggers include corn, wheat, soy and dairy. Many dogs are lactose intolerant, so it's worth knowing how much milk a dog can safely have. Rendered meat meals, artificial preservatives, synthetic colours, filler grains and glycerin (a common moistening agent in treats) can also cause gas and loose stools, so check labels if your dog has recurring soft stools.
Infections and Parasites
Various infections can cause diarrhoea in dogs, ranging from mild to potentially life-threatening. Viral infections pose particular risks to puppies and unvaccinated dogs. Parvovirus is one of the most serious, causing severe, often bloody diarrhoea that can be fatal without prompt treatment.
Bacterial infections from organisms like Salmonella, Campylobacter or E. coli typically produce severe, watery diarrhoea that may contain blood, and need veterinary assessment. Parasites, including roundworms, hookworms, whipworms, coccidia and giardia, are common culprits too, especially in young dogs or those without regular preventive treatment, and can be picked up from contaminated water, soil or other animals. Giardia is particularly known for causing persistent watery diarrhoea that can be hard to resolve without proper treatment.
Medical Conditions That Can Cause Diarrhoea
Sometimes diarrhoea points to an underlying health condition that needs ongoing veterinary management.
- Inflammatory Bowel Disease (IBD) causes chronic intestinal inflammation and recurring digestive issues, usually managed with diet and sometimes medication.
- Pancreatitis often causes diarrhoea alongside vomiting and severe abdominal pain. It can be triggered by high-fat meals and needs immediate veterinary attention.
- Colitis affects the large intestine and typically produces soft stools containing blood and mucus.
- Exocrine Pancreatic Insufficiency (EPI) occurs when the pancreas can't produce enough digestive enzymes, leading to large, foul-smelling, pale, oily stools. Affected dogs often lose weight despite a good appetite.
- Liver disease can show up as diarrhoea, usually with other signs such as weight loss, lethargy and sometimes jaundice.
Toxins, Foreign Bodies and Medications
Toxin ingestion from substances like chocolate, alcohol, certain essential oils or household chemicals can cause severe digestive symptoms alongside other serious effects. Swallowed non-food items such as socks, toys or stones can cause blockages that lead to diarrhoea and need emergency treatment.
Certain medications, particularly antibiotics and anti-inflammatory drugs, can disrupt the normal balance of gut bacteria and cause digestive upset as a side effect.
Common causes of loose stools and diarrhoea in dogs
| Cause | Typical Duration | Key Features |
|---|---|---|
| Dietary indiscretion | 24-48 hours | Sudden onset, dog otherwise well |
| Food change too quick | 2-5 days | Coincides with new food introduction |
| Stress/anxiety | Variable | Links to environmental changes |
| Food sensitivity | Ongoing/recurring | May include skin symptoms |
| Parasites/infection | Persistent until treated | May include blood or mucus |
| Underlying condition (e.g. IBD, EPI) | Ongoing/recurring | Recurring episodes, sometimes weight loss |
For guidance only, not a diagnosis. Contact your vet if diarrhoea lasts more than 24 hours.
When to See a Vet About Diarrhoea or Soft Stools
Emergency Warning Signs
Some situations need immediate veterinary attention, whatever the time of day. If your dog has eaten something toxic or you suspect they've swallowed a foreign object, contact your emergency vet straight away. Don't wait to see if symptoms develop.
Blood in the diarrhoea or vomit is always a serious sign that needs urgent assessment. Severe lethargy, collapse, weakness, persistent vomiting or signs of pain alongside diarrhoea also suggest a more serious problem.
Signs of dehydration include dry, sticky gums, loss of skin elasticity (when you gently lift the skin on the back of the neck, it should spring back immediately) and sunken eyes. Pale gums, difficulty breathing or a swollen abdomen alongside diarrhoea are all emergency signs.
When to Contact Your Vet for Advice
Even without emergency signs, contact your vet if the diarrhoea lasts more than 24 hours, if you notice mucus in the stools, if your dog stops eating, or if episodes keep coming back. Get advice sooner if your dog has an underlying health condition or is taking medication.
Puppies and senior dogs need particular attention, as they can become dehydrated and deteriorate more quickly than healthy adults.
What Your Vet Might Do
Your vet will ask about recent diet, activities and possible exposure to toxins or foreign objects, and examine your dog for fever, abdominal tenderness and dehydration. They may request a fresh stool sample to check for parasites, blood tests for organ function and hydration, X-rays if a foreign body is suspected, or food elimination trials for suspected sensitivities.
Treatment depends on the cause. Fluid therapy addresses dehydration and electrolyte imbalances, anti-parasitic medication targets confirmed parasites, and antibiotics are only prescribed when a bacterial infection is confirmed, not routinely for every case of diarrhoea.
Caring for Mild Diarrhoea at Home
For adult dogs with mild diarrhoea lasting less than 24 hours who otherwise seem bright and well, careful home care may be appropriate whilst you watch for any worsening signs. If symptoms get worse, new signs appear or there's no improvement within 24 hours, contact your vet.
Feeding a Bland Diet
Withholding food isn't necessary for most mild cases. The gentler approach is to offer easily digestible food in small, frequent portions. Never withhold food from puppies, as they need regular nutrition and are at higher risk of dehydration, and don't fast senior dogs or dogs with health conditions without veterinary guidance.
Plain boiled chicken breast with white rice is the classic recovery diet that most dogs tolerate well. Remove all skin and bones and skip seasoning, oils and butter. A commercial gastrointestinal diet recommended by your vet is often preferable, as it's formulated with appropriate nutrients and is easy to digest. Split the day's food into several small meals rather than one or two large ones.
Keeping Your Dog Hydrated
Make sure your dog always has fresh water, and check that they're drinking and urinating normally. If they're reluctant to drink, a small amount of tuna juice (not brine) can make water more appealing, and some dogs will lick ice cubes when they won't drink from a bowl.
Supporting Recovery
Veterinary-approved probiotics may help restore healthy gut bacteria, but check with your vet first, and never give human anti-diarrhoea medication. Once stools firm up, reintroduce their regular food over 2-3 days, slowing down if loose stools return.
Preventing Diarrhoea and Soft Stools
Safe Food Transitions
When changing food, transition over 7-10 days. Start with 25% new food mixed with 75% current food for the first two days, move to 50-50 for days three and four, then 75% new food with 25% current food for days five and six before switching completely.
Monitor stools throughout. Some softening in the first few days is normal, but significant worsening means you should slow the transition or reconsider the new food.
Consistent, Quality Nutrition
A high-quality, consistent diet suited to your dog's age and health is the foundation of good digestion. Foods with recognisable ingredients and shorter ingredient lists often suit sensitive dogs better, and some benefit from diets designed to support digestion. If your dog is older, our complete guide to caring for a senior dog covers diet in more detail, and if they also have stiff joints, see our guide to the best diet for a dog with arthritis.
Keep bins, toxic substances and rich human foods out of reach. If you're unsure about a particular food, check first, for example whether dogs can have butter.
Vaccinations, Parasites and Hygiene
Keep vaccinations up to date to protect against serious viral infections, and maintain year-round parasite prevention as recommended by your vet. On walks, supervise your dog (or keep them on a lead) to stop scavenging and drinking from questionable water sources.
Clean up after animals promptly and wash your hands after handling your dog, especially during illness. Regular, appropriate exercise supports healthy digestion, consistent routines help prevent stress-related upsets, and regular check-ups allow early detection of health issues.
Supporting Joint Health During Recovery
Dogs with digestive upset may be less active than usual, which can affect joint mobility, particularly in older dogs or those already managing joint stiffness. Short, gentle walks help maintain joint flexibility without overexerting them, and dogs already on a joint support routine can usually continue it to help maintain their mobility and comfort. Check with your vet if you're unsure.
Joint supplements containing glucosamine, chondroitin and green-lipped mussel may help support joint health alongside veterinary care. MedPaw's hip and joint supplement, Hip & Joint Chews Max, is a soft chew that also contains MSM, hyaluronic acid and Boswellia serrata. It isn't a treatment for diarrhoea. Because it contains green-lipped mussel, it isn't suitable for dogs with a shellfish allergy, and you should check with your vet before giving it to a pregnant or nursing dog or alongside another joint supplement.
Recovery and Moving Forward
Most dogs with mild loose stools or diarrhoea recover within 2-3 days with appropriate care and monitoring. Recovery time varies with the cause, though: simple dietary indiscretion may settle quickly, whilst conditions like IBD need ongoing management.
If episodes keep recurring, keep a diary of possible triggers, including foods, treats and changes at home, and discuss the pattern with your vet, as it may point to an underlying condition that needs investigating.
When in doubt, it's always better to seek professional advice than to wait and see.
Is runny poop the same as diarrhoea in dogs?
Yes. Diarrhoea means passing loose or liquid stools more often than usual or in larger amounts than normal, so runny or soft poop is a form of diarrhoea. It's a symptom rather than a disease, and the cause can range from eating something unsuitable to infections or underlying health conditions.
How long should I wait before taking my dog to the vet for diarrhoea or runny poop?
If your adult dog has mild diarrhoea but is otherwise bright and eating normally, you can monitor them at home for up to 24 hours. Contact your vet if it lasts longer, if you see mucus, or if your dog stops eating. Seek help immediately if you see blood in the stools, your dog is vomiting, seems lethargic or shows signs of dehydration. Puppies and senior dogs need veterinary attention sooner as they can deteriorate more quickly.
Can I give my dog human anti-diarrhoea medication?
No. Never give your dog human medication without veterinary guidance, as many human medicines can be toxic to dogs. Focus on small, frequent meals of easily digestible food and make sure fresh water is always available. If symptoms persist or worsen, contact your vet for appropriate treatment.
What should I feed my dog when they have diarrhoea or soft stools?
Offer plain boiled chicken breast (skin and bones removed) with white rice, or a commercial gastrointestinal diet recommended by your vet. Avoid seasoning, oils and butter, and split their food into several small meals a day rather than large portions. Avoid fatty foods, dairy and treats until their stools are back to normal, and never give foods that are toxic to dogs, such as onions, garlic or chocolate.
Should I fast my dog if they have runny poop?
Fasting isn't necessary for most mild cases, and small, frequent bland meals are a gentler approach. Never fast puppies, and don't fast senior dogs or dogs with health conditions without veterinary guidance. Always keep fresh water available. If your dog seems unwell in other ways or the stools contain blood, contact your vet rather than managing it at home.
Why does my dog get diarrhoea every time I change their food?
Sudden diet changes are a common cause of diarrhoea because your dog's gut bacteria are adapted to their current food. Transition gradually over 7-10 days: 25% new food for two days, then 50-50, then 75% new food before switching completely. If loose stools persist despite a gradual change, speak to your vet about possible food sensitivities.
Could stress be causing my dog's diarrhoea or soft stools?
Yes. Changes in routine, moving house, new family members, vet visits or separation anxiety can all trigger loose stools in sensitive dogs. Stress hormones like cortisol disrupt the balance of gut bacteria and affect intestinal function. If you suspect stress and symptoms persist, discuss management strategies with your vet.
