When your dog constantly has loose stool, it can be frustrating, messy, and worrying—especially when the problem persists for weeks or seems to come and go unpredictably.
We explain why a dog may constantly have loose stool, what you can do at home, and when to seek veterinary help.
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Dog Constantly Has Loose Stool - Why It Happens
A dog constantly having loose stool may be experiencing food intolerance, parasites, chronic inflammation, digestive imbalance, stress, infection, or underlying health problems. Because persistent loose stool is rarely random, ongoing episodes always deserve attention.
Dog Constantly Has Loose Stool: Common Causes
Food Intolerance or Sensitivity
One of the most common causes of chronic loose stool is food intolerance. Dogs can react poorly to certain proteins—like beef, chicken, lamb, or dairy—or ingredients such as grains, additives, or high-fat foods.
When the immune system identifies an ingredient as irritating, it triggers inflammation in the intestines, causing stool to remain soft, unformed, or greasy.
Dogs with food intolerance often have loose stool that varies from soft to watery, sometimes with mucus.
They may also experience gas, noisy stomachs, itching, recurring ear infections, or vomiting.
The inflammation disrupts nutrient absorption, leading to chronic digestive instability. Even high-quality diets can cause loose stool if the dog is sensitive to one of the ingredients.
Because the reaction is ongoing, the stool rarely becomes fully firm until the problematic ingredient is removed.
Read more: Dog Loose Stool No Other Symptoms (What it means)
Poor Diet or Rapid Food Changes
Feeding low-quality food, high-fat foods, table scraps, or treats loaded with fillers can disrupt the digestive process and lead to constantly loose stool.
Dogs who experience frequent diet changes or who rotate foods abruptly often have difficulty adjusting, and the intestines become inflamed from inconsistency.
High-fat foods overwhelm the pancreas and intestines, speeding up digestion and making it harder for the colon to absorb water. This results in soft or mushy stool repeatedly.
Rapid diet changes disrupt gut bacteria and irritate the digestive lining, causing loose stool that does not stabilize until the gut flora rebalances.
Intestinal Parasites
Parasites are a major cause of chronic loose stool, especially in young dogs, rescue dogs, or dogs who spend time outdoors. Parasites like Giardia, whipworms, hookworms, roundworms, coccidia, and tapeworms irritate the intestines and prevent proper absorption of nutrients.
Giardia is particularly known for soft, greasy, or mucusy stool that becomes chronic without treatment. Whipworms cause intermittent diarrhea with weight loss or straining.
Because parasite infections can come and go in severity, the stool may temporarily look better before becoming loose again.
Even dogs on preventatives can become infected, especially if they drink from puddles, shared bowls, lakes, or contaminated soil.
Chronic Inflammation
Inflammatory bowel disease causes long-term inflammation in the stomach or intestines. Dogs with IBD may have consistently loose stool, sometimes with mucus, straining, or variable texture.
The inflammation disrupts how the gut processes food, causing chronic irritation that leads to unformed stool.
These dogs may also experience vomiting, weight loss, decreased appetite, or periods of symptom flare-ups.
IBD often worsens over time without treatment, and stress or new foods can trigger additional flare-ups. Because the inflammation is ongoing, stool consistency rarely stabilizes on its own.
Stress
Stress affects the digestive system in dogs just like in humans. When a dog’s stress hormone levels rise, intestinal movement accelerates, causing loose stool.
Dogs may develop chronic loose stool when exposed to:
• New environments
• Family changes
• Separation anxiety
• Loud noises
• Travel
• New pets
• Schedule disruptions
Stress-related digestive upset often appears suddenly, but repeated stress leads to chronic episodes. The colon becomes more reactive, producing soft or mushy stool as the dog struggles to regulate its gut function.
Bacterial or Viral Infections
Some dogs develop chronic loose stool from bacterial overgrowth or low-grade infections in the gut.
Clostridium, Salmonella, and E. coli can all cause repeated soft stool, gas, and abdominal discomfort. Viral infections—especially in younger dogs—may create cycles of soft stool that never fully resolve until the immune system clears the infection.
Even after the infection fades, inflammation can persist, causing ongoing loose stool until the gut fully recovers.
Digestive Enzyme Insufficiency or Pancreatic Issues
The pancreas produces enzymes that help digest food properly. When the pancreas becomes inflamed (pancreatitis) or fails to produce enough enzymes (EPI—exocrine pancreatic insufficiency), the dog cannot digest fat or nutrients effectively.
This leads to chronic loose stool that may look greasy, pale, or large in volume. Dogs may eat excessively, lose weight, or appear hungry but fail to gain weight.
Pancreatic issues require medical diagnosis and specialized management, as the loose stool will continue until the underlying condition is treated.
Gut Flora Imbalance
The digestive tract depends on healthy bacteria to break down nutrients. Antibiotics, illness, dietary changes, or stress can disrupt gut flora, causing long-term loose stool. Without a proper bacterial balance, the intestines become irritated and overreactive.
Dogs with gut imbalance may experience inconsistent stool texture, gas, and occasional bloating. Recovery often requires time, probiotics, and stabilized diet routines.
Read more: Dog Loose Stool but Not Diarrhea (What it means)
What to Do If Your Dog Constantly Has Loose Stool
Start by evaluating your dog’s recent routine. Consider whether there were diet changes, new treats, stressors, or access to inappropriate foods. Begin feeding a bland, easily digestible diet such as boiled chicken and rice, or a veterinary digestive formula designed to stabilize stool.
Provide small, frequent meals instead of large portions. This supports gentle digestion and prevents overwhelming the intestines.
Ensure your dog has constant access to fresh water, as loose stool leads to fluid loss.
Avoid treats, table scraps, or flavored chews until the stool improves. Keep your dog away from standing water outdoors and clean up stool promptly to reduce reinfection risk if parasites are involved.
Monitor your dog’s stool closely for 24–48 hours. If the loose stool improves with dietary changes, gradually transition back to their regular food over several days.
If your dog frequently experiences loose stool, consider a long-term diet trial to identify food sensitivities. Supporting the gut with probiotics or specially formulated digestive supplements may help restore healthy gut flora.
If loose stool is persistent or accompanied by other symptoms, veterinary evaluation is essential to rule out infection, parasites, IBD, pancreatic issues, or chronic digestive disease.
When to Call or Visit Your Vet
Contact your veterinarian promptly if your dog:
• Has loose stool lasting more than 48 hours.
• Has mucus, blood, or dark stool.
• Vomits repeatedly or refuses food.
• Appears lethargic or weak
• Shows weight loss or chronic gas.
• Has recurring soft stool even with diet changes.
• Shows belly discomfort or bloating.
• Drinks excessively or becomes dehydrated.
• Has recently eaten garbage, spoiled food, or foreign objects.
• Is a puppy, senior dog, or has chronic medical conditions.
Seek emergency care if:
• Stool becomes black or tar-like.
• Your dog is unable to keep water down.
• The abdomen becomes firm, swollen, or painful.
• Severe diarrhea appears suddenly.
• Your dog collapses or appears disoriented.
Chronic loose stool can signal serious underlying illness and should never be ignored.
Read more: Dog constantly being sick (Here’s why)
Key Takeaway
A dog constantly having loose stool is almost always dealing with ongoing irritation, sensitivity, inflammation, stress, or underlying digestive disease.
Occasional loose stool may be normal, but chronic episodes signal that your dog’s gut is struggling. With proper diet adjustments, close monitoring, and veterinary care when needed, most dogs regain normal stool consistency and improved digestive health.