Your Dog Has Diarrhoea: Causes, Treatment & When to Worry
Your dog has diarrhoea — here's what causes it, when it's an emergency, vet diagnosis costs, treatment options, and proven home care strategies.
If your dog has diarrhoea, you're dealing with one of the most common reasons pet owners visit veterinary clinics. Canine diarrhoea — defined as the passage of loose, watery, or unformed stools more frequently than normal — affects an estimated 20-30% of dogs at some point each year, according to data compiled in the Merck Veterinary Manual. It isn't a disease itself but a clinical sign pointing to an underlying disruption somewhere along the gastrointestinal (GI) tract. Causes range from simple dietary indiscretion (your dog raided the trash) to life-threatening conditions like parvovirus or intestinal blockage. Most acute cases resolve within 48-72 hours with supportive care, but persistent or severe diarrhoea demands professional veterinary evaluation to identify the root cause and prevent dangerous dehydration.
What Causes Diarrhoea in Dogs?
Understanding why your dog has diarrhoea starts with recognizing that the GI tract is a complex system sensitive to dozens of potential disruptors. Veterinarians broadly categorize diarrhoea by origin and duration, which determines the diagnostic and treatment approach.
Acute vs. Chronic Diarrhoea
Acute diarrhoea appears suddenly and typically lasts fewer than 14 days. It's most often linked to dietary indiscretion, infections, parasites, toxin ingestion, or stress. The majority of acute cases are self-limiting — meaning they resolve on their own or with minimal intervention.
Chronic diarrhoea persists beyond 14 days or recurs repeatedly over weeks to months. This pattern signals deeper issues: inflammatory bowel disease (IBD), food allergies or intolerances, exocrine pancreatic insufficiency (EPI), chronic parasitism, or neoplasia (cancer). Chronic cases require thorough diagnostic workups and rarely resolve without targeted treatment.
Common Causes by Category
| Category | Specific Causes | Typical Duration |
|---|---|---|
| Dietary | Sudden food changes, table scraps, garbage ingestion, food intolerance, food allergy | 1-5 days (acute) or ongoing (chronic allergy) |
| Infectious | Parvovirus, canine coronavirus, Salmonella, Campylobacter, Clostridium perfringens, Giardia, Coccidia | 5-14 days (varies with pathogen) |
| Parasitic | Roundworms, hookworms, whipworms, tapeworms, Giardia | Chronic until dewormed |
| Toxin/Foreign Body | Xylitol, chocolate, plants, fabric/toy ingestion causing partial obstruction | Ongoing until removed/treated |
| Inflammatory/Immune | IBD, hemorrhagic gastroenteritis (HGE/AHDS), food-responsive enteropathy | Chronic; requires long-term management |
| Organ Dysfunction | Exocrine pancreatic insufficiency (EPI), liver disease, kidney disease, Addison's disease | Chronic; lifelong management |
| Stress-Related | Boarding, travel, new pets, loud environments (stress colitis) | 2-5 days after stressor removal |
| Medication-Induced | NSAIDs (carprofen, meloxicam), antibiotics (amoxicillin-clavulanate), chemotherapy agents | Resolves after drug discontinuation |
Symptom Checklist: Early Warning Signs vs. Emergency Red Flags
Not all diarrhoea episodes carry the same risk. Use this severity-based checklist to determine whether your dog needs monitoring at home or immediate veterinary attention. The American Veterinary Medical Association (AVMA) recommends seeking professional care whenever multiple severe symptoms appear together.
| Severity Level | Symptoms | Action Required |
|---|---|---|
| Mild (Monitor at Home) |
• 1-2 episodes of soft/loose stool • Normal appetite maintained • Normal energy level • No blood or mucus visible • Dog is drinking water normally • No vomiting | Fasting for 12-24 hours (adult dogs only), then bland diet. Monitor for 48 hours. |
| Moderate (Call Vet for Advice) |
• 3+ episodes within 24 hours • Mild lethargy • Decreased but present appetite • Small amounts of mucus in stool • Slight straining to defecate • Mild abdominal discomfort (restlessness) | Phone your vet for guidance. Schedule appointment within 24-48 hours if not improving. |
| Severe (Emergency Vet Visit) |
• Blood in stool (fresh red or dark/tarry black) • Vomiting alongside diarrhoea • Complete refusal to eat or drink for 12+ hours • Signs of dehydration (tacky gums, sunken eyes, skin tenting) • Severe lethargy or collapse • Distended/painful abdomen • Fever above 103.5°F (39.7°C) • Diarrhoea lasting more than 48 hours • Known toxin or foreign body ingestion | Seek emergency veterinary care immediately. These signs can indicate parvovirus, hemorrhagic gastroenteritis, intestinal obstruction, or severe dehydration requiring IV fluids. |
🚨 When to See the Vet Immediately
Don't wait if your dog has diarrhoea AND any of the following:
- Puppy under 6 months — puppies dehydrate dangerously fast; parvovirus can kill within 48-72 hours
- Bloody or black, tarry stool — indicates active GI bleeding (hemorrhagic gastroenteritis, ulceration, or parvovirus)
- Concurrent vomiting — unable to keep fluids down accelerates dehydration
- Known ingestion of toxins (xylitol, grapes/raisins, rodenticide, human NSAIDs) — call ASPCA Animal Poison Control at (888) 426-4435 (24/7, consultation fee applies) or Pet Poison Helpline at (855) 764-7661
- Unvaccinated or recently adopted dog — higher parvovirus and parasite risk
- Senior dog (7+ years) or dog with pre-existing conditions (kidney disease, diabetes, Addison's)
- No improvement after 48 hours of home management
Risk Factors: Which Dogs Are Most Vulnerable?
While any dog can develop diarrhoea, certain factors significantly increase susceptibility and the likelihood of severe outcomes:
Breed Predispositions
Some breeds carry genetic or anatomical traits that make chronic GI issues more likely:
- German Shepherds — higher rates of EPI (exocrine pancreatic insufficiency) and chronic enteropathies; estimated 1 in 100 German Shepherds develops EPI
- Boxers — predisposed to histiocytic ulcerative colitis (Boxer colitis), a specific form of IBD often involving E. coli infiltration of the colon
- Yorkshire Terriers, Miniature Schnauzers — prone to protein-losing enteropathy and lymphangiectasia
- Shar-Peis — elevated risk of inflammatory bowel disease and cobalamin (B12) malabsorption
- Labrador Retrievers, Golden Retrievers — higher food allergy prevalence; dietary indiscretion due to indiscriminate eating habits
- Brachycephalic breeds (French Bulldogs, Bulldogs, Pugs) — sensitive GI tracts often linked to concurrent food allergies and environmental atopy
Age-Related Risk
Puppies (under 6 months): Immature immune systems and incomplete vaccination status make puppies extremely vulnerable to parvovirus (mortality rate 16-35% even with treatment, per Merck Veterinary Manual), parasites, and rapid dehydration. Any diarrhoea in an unvaccinated puppy warrants same-day veterinary evaluation.
Senior dogs (7+ years): Higher incidence of GI neoplasia (lymphoma, adenocarcinoma), organ dysfunction (kidney/liver disease), and medication-related GI upset from chronic NSAID use for arthritis.
Environmental & Lifestyle Factors
- Multi-dog households and kennel environments — increased pathogen transmission (Giardia, Campylobacter)
- Raw food diets — FDA has documented Salmonella and Listeria contamination risks in raw diets; dogs may shed bacteria asymptomatically or develop clinical GI signs
- Frequent diet changes — dogs fed different brands/flavors frequently have higher rates of diet-responsive enteropathy
- High-stress lifestyles — competition dogs, recently rehomed dogs, and dogs with separation anxiety show elevated stress colitis rates
- Outdoor/rural dogs — higher exposure to parasites, contaminated water sources, wildlife feces, and toxic plants
How Veterinarians Diagnose the Cause of Diarrhoea
When your dog has diarrhoea that warrants veterinary attention, the diagnostic process follows a tiered approach — starting with non-invasive tests and escalating based on findings. Here's what to expect at the clinic and what each test costs.
Diagnostic Pathway: Step by Step
- Physical Examination ($55-$95 office visit fee)
Vet assesses hydration status (skin tent test, gum moisture), palpates abdomen for pain/masses/foreign bodies, checks temperature (normal: 101-102.5°F / 38.3-39.2°C), evaluates body condition score (BCS), and reviews dietary and vaccination history. - Fecal Analysis ($35-$75)
Fecal flotation (detects parasite eggs), fecal ELISA/antigen test for Giardia ($25-$40 add-on), and fecal cytology (checks for abnormal bacteria, white blood cells indicating inflammation). Many vets also run a fecal PCR panel ($85-$150) that screens for 10-15 pathogens simultaneously including parvovirus, Campylobacter, Salmonella, and Clostridium perfringens toxin genes. - Blood Work — CBC and Chemistry Panel ($120-$250)
Complete blood count (CBC) reveals infection (elevated white cells), anemia (from GI bleeding), and dehydration (elevated red cell count/hematocrit). Chemistry panel assesses organ function — kidney values (BUN, creatinine), liver enzymes (ALT, ALP), electrolytes (sodium, potassium, chloride — often deranged with severe diarrhoea), and total protein/albumin (low levels suggest protein-losing enteropathy). - Imaging — Abdominal X-rays or Ultrasound ($200-$500)
Indicated when foreign body ingestion, intussusception (telescoping intestine), masses, or organ enlargement is suspected. Ultrasound provides superior soft-tissue detail of intestinal wall layering and mesenteric lymph nodes. X-rays are faster and better for detecting metallic foreign objects or free abdominal gas (suggesting perforation). - Advanced Diagnostics (if chronic or unresponsive)
• Canine pancreatic lipase (Spec cPL) — $80-$130 — rules out pancreatitis
• Cobalamin (B12) and folate levels — $60-$100 — assesses small intestinal absorption
• TLI (trypsin-like immunoreactivity) — $70-$110 — diagnoses EPI
• Food allergy elimination trial — $80-$180 for prescription hydrolyzed diet over 8-12 weeks
• Endoscopy with biopsy — $1,200-$2,800 — gold standard for diagnosing IBD vs. lymphoma vs. other infiltrative diseases
Typical Diagnostic Costs Summary
| Diagnostic Tier | Tests Included | Estimated Cost Range |
|---|---|---|
| Basic (acute, mild case) | Exam + fecal flotation + Giardia test | $90-$170 |
| Intermediate (moderate/persistent) | Basic + CBC/chemistry + fecal PCR panel | $300-$550 |
| Advanced (chronic/severe) | Intermediate + imaging + Spec cPL + cobalamin/folate | $600-$1,100 |
| Comprehensive (refractory cases) | All above + endoscopy/biopsy or surgical biopsy | $1,800-$3,500 |
Treatment Options for Diarrhoea in Dogs
Treatment depends entirely on the underlying cause and severity. Most acute, uncomplicated cases respond well to conservative supportive care, while severe or chronic conditions require targeted medical or surgical intervention.
| Treatment Approach | Indications | Details & Medications | Success Rate / Outcome |
|---|---|---|---|
| GI Rest + Bland Diet | Mild acute diarrhoea, dietary indiscretion | 12-24 hour fast (adult dogs only — never fast puppies or toy breeds due to hypoglycemia risk), then boiled chicken breast + white rice (2:1 ratio) or prescription GI diet (Hill's i/d, Royal Canin GI, Purina EN) for 3-5 days before gradual transition back to regular food | 70-80% of mild acute cases resolve within 48-72 hours |
| Probiotics | Acute and antibiotic-associated diarrhoea | Veterinary-specific strains: Enterococcus faecium (Purina FortiFlora, $28-$35/30 packets), Saccharomyces boulardii (Proviable-DC, $25-$35/30 capsules). Multi-strain products (Proviable KP, Visbiome Vet) for more severe dysbiosis | Reduces duration of acute diarrhoea by approximately 1-2 days in clinical studies |
| Anthelmintics (Dewormers) | Confirmed parasitic infection | Fenbendazole (Panacur) 50 mg/kg PO daily x 3-5 days for roundworms, hookworms, whipworms, Giardia. Praziquantel for tapeworms. Pyrantel pamoate (Nemex) for roundworms/hookworms. Repeat fecal at 2-4 weeks to confirm clearance | 90-95% cure rate with appropriate dewormer; Giardia may require 2 courses |
| Antibiotics | Bacterial overgrowth, hemorrhagic gastroenteritis, specific infections | Metronidazole 10-15 mg/kg PO twice daily (common first-line; also anti-inflammatory in colon). Tylosin 10-20 mg/kg PO twice daily for tylosin-responsive diarrhoea. Amoxicillin-clavulanate for secondary bacterial overgrowth. NOTE: Current veterinary consensus discourages routine antibiotic use for uncomplicated acute diarrhoea — most cases do not benefit | Effective when bacterial etiology confirmed; overuse contributes to antibiotic resistance |
| IV Fluid Therapy | Moderate to severe dehydration, HGE, parvovirus | Crystalloid fluids (LRS or Normosol-R) at calculated maintenance + dehydration deficit rate. Typically 24-72 hours of hospitalization. Electrolyte correction (potassium supplementation common). May include anti-nausea medications (maropitant/Cerenia 1 mg/kg IV/SQ or 2 mg/kg PO) | HGE survival rate: 90-95% with aggressive fluid therapy. Parvovirus: 65-84% with intensive care |
| Immunosuppressive Therapy | Confirmed IBD, immune-mediated enteropathy | Prednisone 1-2 mg/kg/day tapering over 8-12 weeks. Budesonide (enteric-targeted steroid) 1-3 mg/dog/day for reduced systemic side effects. Chlorambucil or cyclosporine for refractory cases. Always combined with dietary management | 70-80% of IBD dogs achieve remission with diet + medication combination; some require lifelong low-dose therapy |
| Surgery | Intestinal obstruction, intussusception, discrete tumor, perforation | Exploratory laparotomy with enterotomy (removal of foreign body) or intestinal resection and anastomosis (removal of diseased segment). Post-operative hospitalization 2-5 days typical | Foreign body removal: 90-95% survival. Intestinal resection for neoplasia: 50-70% survival depending on tumor type and staging |
A Note on Over-the-Counter Medications
Some owners reach for human anti-diarrhoeal medications. Exercise caution:
- Loperamide (Imodium): Can be used in dogs at 0.1 mg/kg PO every 8-12 hours — BUT is contraindicated in herding breeds (Collies, Australian Shepherds, Shelties) with the MDR1 gene mutation, which allows the drug to cross the blood-brain barrier and cause severe neurotoxicity. Never use without veterinary guidance.
- Bismuth subsalicylate (Pepto-Bismol): Sometimes used at 1 mL/kg every 6-8 hours, but contains salicylate (aspirin-family) — avoid in dogs on NSAIDs, dogs with bleeding disorders, or cats in the household who could accidentally ingest it. Can turn stool black, masking GI bleeding.
- Kaolin-pectin products: Generally safe but modestly effective; mainly coat the intestinal lining and absorb some toxins.
Always consult your veterinarian before giving any OTC medication to your dog, especially if they take other medications or have pre-existing health conditions.
Home Care and Management: What to Do Right Now
For mild, uncomplicated cases where your dog is otherwise bright and hydrated, structured home care can resolve the issue within 2-3 days. Here's a practical protocol:
Step 1: Short Fast (Adult Dogs Only)
Withhold food for 12-24 hours to allow the GI tract to rest. Do NOT fast:
- Puppies under 12 months (risk of hypoglycemia)
- Toy breeds under 15 lb / 7 kg (Chihuahuas, Yorkies — hypoglycemia risk)
- Diabetic dogs (insulin timing requires consistent food intake)
- Dogs with a history of pancreatitis (prolonged fasting can worsen the condition)
During the fast, offer fresh water frequently. Ice cubes can encourage drinking if your dog is reluctant. You can also offer unflavored Pedialyte (diluted 50/50 with water) or bone broth (low-sodium, no onions or garlic) to maintain electrolyte balance.
Step 2: Bland Diet Introduction
After the fasting period, introduce a bland diet in small portions — approximately 1/4 of the normal meal size, offered every 3-4 hours:
| Dog Weight | Daily Bland Diet Amount (divided into 4 meals) | Chicken + Rice Ratio |
|---|---|---|
| Under 15 lb (7 kg) | ¾ - 1 cup total per day | 1 part boiled chicken breast : 2 parts white rice |
| 15-30 lb (7-14 kg) | 1½ - 2 cups total per day | 1:2 ratio |
| 30-60 lb (14-27 kg) | 2½ - 4 cups total per day | 1:2 ratio |
| 60-100 lb (27-45 kg) | 4 - 6 cups total per day | 1:2 ratio |
| Over 100 lb (45+ kg) | 6 - 8 cups total per day | 1:2 ratio |
Preparation: Boil boneless, skinless chicken breast (no seasoning, no oil). Cook white rice in plain water (not broth — commercial broths often contain onion powder). Let both cool to room temperature before serving. Canned plain pumpkin (NOT pie filling — which contains xylitol and spices) can be added at 1-2 tablespoons per meal for soluble fiber, which helps firm stools.
Step 3: Gradual Transition Back
Once stools are formed for 2 consecutive days, begin mixing the bland diet with your dog's regular food over 4-5 days:
- Days 1-2: 75% bland diet, 25% regular food
- Days 3-4: 50% bland diet, 50% regular food
- Day 5: 25% bland diet, 75% regular food
- Day 6: 100% regular food
Step 4: Ongoing Monitoring
Track stool consistency using the Purina Fecal Scoring System (1 = hard pellets, 7 = watery with no solid content). Ideal is score 2-3 (formed, firm, pick-up-able). Photograph abnormal stools to show your vet — color, consistency, frequency, and presence of mucus or blood are all diagnostically relevant.
Prognosis and Expected Outcomes
The prognosis for a dog with diarrhoea varies enormously based on the underlying cause, the dog's age and overall health, and how quickly appropriate treatment begins.
| Condition | Typical Recovery Time | Prognosis / Survival Rate | Long-Term Outlook |
|---|---|---|---|
| Dietary indiscretion (mild) | 24-72 hours | Excellent — near 100% recovery | Full recovery; no lasting effects |
| Parasitic infection | 1-2 weeks after deworming | Excellent with treatment (95%+) | Full recovery; reinfection possible without prevention |
| Bacterial gastroenteritis | 5-14 days | Good to excellent with supportive care | Full recovery typical |
| Hemorrhagic gastroenteritis (AHDS) | 3-7 days with hospitalization | 90-95% survival with aggressive IV fluids; poor without treatment | Most dogs fully recover; 10-15% recurrence rate |
| Parvovirus (treated) | 5-10 days hospitalized; 2-3 weeks full recovery | 65-84% with intensive care; <10% without treatment | Survivors typically have lifelong immunity; rare chronic GI sensitivity |
| IBD (inflammatory bowel disease) | Weeks to months to achieve remission | Manageable in 70-80% of cases; guarded if protein-losing enteropathy develops | Lifelong management required; normal lifespan if well-controlled |
| Intestinal lymphoma | Variable | Low-grade: median survival 18-30 months with chemotherapy. High-grade: median survival 6-12 months | Palliative care; not curable but remission achievable |
| Foreign body obstruction | 2-5 days post-surgery; 2 weeks full recovery | 90-95% with timely surgery; drops to 50-70% if perforation/peritonitis occurs | Full recovery typical; prevent future access to foreign objects |
Total Cost of Diarrhoea Treatment in Dogs
Costs vary widely depending on severity and underlying cause. Here's a realistic breakdown based on typical US veterinary pricing in 2025-2026:
| Scenario | Components | Estimated Total Cost |
|---|---|---|
| Mild acute case | Office visit + fecal test + probiotic + bland diet | $120-$250 |
| Moderate case with bloodwork | Office visit + fecal panel + CBC/chemistry + medications (metronidazole, probiotics, anti-nausea) | $350-$700 |
| HGE / severe dehydration | Emergency visit + bloodwork + 24-48 hours IV fluids + injectable medications + monitoring | $1,200-$3,000 |
| Parvovirus treatment | Emergency visit + diagnostics + 5-7 days hospitalization + IV fluids + antibiotics + anti-nausea + isolation care | $2,500-$6,000+ |
| Chronic IBD workup + management | Full diagnostics + food trial + possible endoscopy/biopsy + long-term medications | $2,000-$5,000 initial; $100-$300/month ongoing |
| Foreign body surgery | Diagnostics + surgery + 2-5 days hospitalization + post-op care | $2,500-$7,000 |
Cost-saving tips: Pet insurance with accident-and-illness coverage typically reimburses 70-90% of eligible expenses after deductible. If uninsured, ask your vet about CareCredit or Scratchpay payment plans. Community veterinary clinics and veterinary school teaching hospitals often offer reduced-cost diagnostics.
Prevention Strategies
While you can't prevent every episode, these evidence-based strategies significantly reduce diarrhoea frequency:
- Consistent diet: Avoid frequent brand/flavor changes. When transitioning foods, mix gradually over 7-10 days (25% new food increasing by 25% every 2-3 days).
- Monthly parasite prevention: Broad-spectrum products like Simparica Trio, Interceptor Plus, or NexGard Plus cover intestinal parasites alongside heartworm and flea/tick prevention. Yearly fecal testing (1-2x/year) catches subclinical infections.
- Complete vaccination: DHPP vaccine (covers parvovirus, distemper, adenovirus, parainfluenza) — puppies need the full series at 6-8, 10-12, and 14-16 weeks with a booster at 1 year. Bordetella vaccine for dogs in social settings (boarding, daycare, grooming).
- Trash and counter management: Use dog-proof trash cans with locking lids. Train a solid "leave it" cue using positive reinforcement methods — reward-based training builds reliable impulse control without fear or punishment.
- Avoid toxic foods: Grapes/raisins, xylitol (sugar-free gum, peanut butter), chocolate, macadamia nuts, onions, garlic, and fatty table scraps are common culprits. Educate all household members and guests.
- Probiotic supplementation during stress: Start FortiFlora or Proviable 2-3 days before known stressors (boarding, travel, fireworks season) and continue through the event to support gut microbiome stability.
- Water hygiene: Prevent drinking from puddles, ponds, and standing water where Giardia and Leptospira thrive. Carry fresh water on walks.
- Limit raw diet risks: If feeding raw, follow FDA safe-handling guidelines — freeze meat at -4°F (-20°C) for at least 7 days to reduce parasite load, practice strict kitchen hygiene, and have your dog's feces tested quarterly.
Frequently Asked Questions
Can I give my dog rice for diarrhoea?
Yes — plain white rice is a standard component of the veterinary-recommended bland diet. White rice is preferred over brown rice during GI upset because it's lower in fiber and easier to digest. Combine with boiled, unseasoned chicken breast in a 2:1 rice-to-chicken ratio. Feed small, frequent meals (4 per day) rather than one large meal. Continue the bland diet until stools are formed for 2 consecutive days, then transition gradually back to regular food over 4-5 days.
How long is too long for a dog to have diarrhoea?
For adult dogs in good health, 24-48 hours of mild diarrhoea with normal behavior and appetite is the threshold for home monitoring. If diarrhoea persists beyond 48 hours without improvement, or if any red-flag symptoms develop at any point (blood in stool, vomiting, lethargy, dehydration), seek veterinary care immediately. For puppies, senior dogs, or dogs with pre-existing conditions, contact your vet within 12-24 hours of diarrhoea onset.
Is pumpkin good for dogs with diarrhoea?
Canned plain pumpkin (100% pumpkin, NOT pumpkin pie filling) is an effective, safe home remedy. The soluble fiber in pumpkin absorbs excess water in the GI tract and adds bulk to loose stools. Dosing: 1-2 teaspoons per meal for dogs under 20 lb (9 kg), 1-2 tablespoons per meal for dogs 20-60 lb (9-27 kg), and 2-4 tablespoons per meal for dogs over 60 lb (27+ kg). Pumpkin is a supportive measure, not a treatment for underlying disease — if diarrhoea doesn't improve within 24-48 hours of adding pumpkin, consult your veterinarian.
Should I starve my dog if they have diarrhoea?
A 12-24 hour fast can help adult dogs by giving the GI tract a rest, but fasting is not appropriate for puppies under 12 months, toy breeds under 15 lb (7 kg), diabetic dogs, or dogs with pancreatitis. These dogs risk dangerous hypoglycemia (low blood sugar) without regular meals. Even during a fast, fresh water must be available at all times. After the fast, introduce bland food in small portions — never return to full-size meals immediately.
Can stress cause diarrhoea in dogs?
Yes — stress colitis is a well-documented condition in dogs. The gut-brain axis means emotional stress (boarding, moving, new pets, loud noises, separation anxiety) directly affects intestinal motility and mucosal integrity. Stress-induced diarrhoea typically appears within 24-48 hours of the trigger and resolves within 3-5 days once the stressor is removed. Probiotics started before anticipated stressful events can help prevent episodes. For chronic anxiety-related GI issues, consult your vet about behavioral modification plans and, if needed, anti-anxiety medications like trazodone or fluoxetine.
What does the color of my dog's diarrhoea mean?
Stool color provides diagnostic clues:
• Brown (normal shades) — likely dietary or mild GI upset
• Yellow/orange — rapid transit through the GI tract; may indicate liver or gallbladder involvement if persistent
• Green — could indicate grass ingestion (common and usually harmless) or, if persistent, gallbladder issues
• Red streaks/bright red blood (hematochezia) — lower GI bleeding from the colon or rectum; common with colitis, parasites, or anal gland issues
• Black, tarry (melena) — upper GI bleeding (stomach or small intestine); digested blood turns black. This is an emergency — seek veterinary care immediately
• Grey/white — possible biliary obstruction or excessive bone content in raw diets; warrants veterinary evaluation
Is diarrhoea contagious between dogs?
It depends on the cause. Infectious agents like parvovirus, Giardia, Campylobacter, and Salmonella are highly contagious between dogs through fecal-oral transmission. If one dog in your household has infectious diarrhoea, isolate them from other dogs, pick up feces immediately, disinfect shared areas with a 1:30 bleach solution (effective against parvovirus), and have all dogs tested. Non-infectious causes (dietary indiscretion, stress, food allergies) are not contagious.
This article is for informational purposes only and does not replace professional veterinary advice. If your dog has diarrhoea accompanied by blood, vomiting, lethargy, or dehydration, contact your veterinarian or an emergency animal hospital immediately. For suspected toxin ingestion, call ASPCA Animal Poison Control at (888) 426-4435 or Pet Poison Helpline at (855) 764-7661.
Jonas Cole
All our authors care for dogs every day — read more of their work on the authors page.
