Why Is Your Dog Having Diarrhea
📝 Summary
Dog diarrhea ranges from diet and bacterial/viral infection to toxins, parasites, maldigestion, inflammatory bowel, and stress. Acute vs chronic forms guide the cause. Blood, lethargy, or persistence beyond a day or two calls for a vet.
1 Causes of acute diarrhea
Dietary: allergic or irritating food, toxins, or a sudden food change. Bacterial: E. coli, Campylobacter, salmonella. Viral: distemper, parvovirus, coronavirus, infectious hepatitis, often with vomiting then watery, foul, mucus stool that can turn bloody. Toxic: pesticides, rodenticides, or certain drugs, where the stool’s look can hint at the poison (arsenic: rice-water stool; mercury: black, mucous, bloody; phosphorus: glows in the dark). Nervous: cold or other triggers raise parasympathetic activity, speeding the gut. And blockage, uremia, or Addison’s disease can also appear as diarrhea.
2 Causes of chronic diarrhea
Maldigestion: poor starch/sugar breakdown brings rumbling, pain, and soft stool with starch; poor protein breakdown gives foul, watery, alkaline stool; poor fat breakdown (often from pancreatic insufficiency) gives gray, fatty stool. Inflammatory: chronic enteritis with alternating constipation and diarrhea. Toxic: endotoxin buildup. Parasitic: worms in the gut, with eggs or worms in the stool. Stress: cold or overeating triggers soft or watery stool after some formed stool. Nutritional: secondary to other diseases such as liver, kidney, or blood disorders. And gut tumors, ulcers, lymphatic issues, or hypothyroidism can all drive chronic diarrhea.
3 When to worry
A single soft stool is often minor, but blood, lethargy, vomiting, or diarrhea that lingers beyond a day or two, especially in puppies, deserves a veterinary check to find the root cause.
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