It’s a moment most dog parents — standing in the park or backyard, looking down and thinking, “That doesn’t look quite right…”
While it’s not the most glamorous part of dog parenthood, keeping an eye on your pup’s stools is one of the simplest ways to track their health.
If you’ve noticed black poo, it’s natural to feel concerned. While sometimes it signals a health issue, it can also be linked to diet or medications.
Let’s break it down — what’s happening, what to do, and how to keep your pup happy and healthy.
What a healthy stool looks like
A healthy stool should be:
Medium to light brown
Log-shaped and firm, but not hard
Easy to pick up — not too wet, sticky or crumbly
Free from visible mucus, blood, worms or undigested food
When your dog’s daily deposits tick these boxes, it’s a good sign their gut health is thriving. If not, it’s time to investigate.
Black dog poo: common causes and treatments
Noticing black poo in your pup’s latest bathroom trip? Here’s what could be causing it — and how you can help them bounce back to full health.
1. Diet
Cause: Rich, dark-coloured foods like organ meats (especially liver) or charcoal-based treats can darken stools. Dogs who scavenge may also eat things that change stool colour.
What to do: Review their meals and watch their bowel habits. Supervise outdoor time to minimise scavenging and ensure they’re feeling satisfied after meals. A fresh, balanced diet makes it easier to keep things regular — in every sense of the word.
2. Iron supplements or medications
Cause: Iron supplements and medications with bismuth (used for upset stomachs) often cause black, tarry stools.
What to do: Think their medication could be the cause? Check with your vet to see if this could be the case.
3. Gastrointestinal bleeding (melena)
Cause: Black, tarry stools may mean digested blood from internal bleeding in the upper gastrointestinal tract. Possible causes include IBD, toxin ingestion, clotting disorders, cancer, ulcers, parasites or foreign objects (see below).
What to do: Book a veterinary appointment as soon as possible for a full health check.
4. Gastrointestinal ulcers
Cause: Chronic non-steroidal anti-inflammatory drugs (NSAID) use, stress or underlying conditions like liver disease can lead to bleeding ulcers. (Rephrased for clearer cause-and-effect)
What to do: Your vet may prescribe medications to protect the stomach lining and treat any underlying causes.
Read more: Top 5 types of dog anxiety and how to treat them naturally
5. Parasites
Cause: Parasites like hookworms or whipworms can damage the intestinal lining, causing bleeding and black stools.
What to do: Ask your vet for a faecal test and discuss the best deworming options for your dog.
6. Foreign objects
Cause: Dogs often explore the world with their mouths, especially puppies. Sometimes they may ingest inedible items which can cause bleeding in their gastrointestinal tract.
What to do: Eating inedible objects can cause blockages as well as bleeding. Speak to your vet about your concerns. If it’s a regular occurrence, your pup may have pica – an eating disorder characterised by eating non-food items.
Black stools vs. red blood in stools — what’s the difference?
Both are signs of bleeding, but the location differs:
Black stools (melena): Indicate bleeding in the upper GI tract, including the small intestines.
Red blood (hematochezia): Fresh blood from the lower GI tract, often linked to anal gland issues, colitis or injury.
If you see either, trust your instincts and chat with your vet – bringing a sample along can help speed up the diagnosis.
The colour of your dog’s poo – yellow, green, pink, grey, white, or dark brown – can be a great indication of healthiness or health issues.
Read more: Dog poo decoded: colour, consistency and smell (vet approved guide)
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When to call the vet
If you’re ever unsure, it’s always better to play it safe and speak to your vet. But some signs mean you shouldn’t wait:
Black, tarry stools that appear more than once
Vomiting or signs of nausea like lip licking, drooling or swallowing repeatedly
Lethargy or weakness — if your dog seems unusually tired or uninterested in their usual activities
Pale gums or signs of anaemia, such as rapid breathing or cold paws
Loss of appetite or significant weight loss
Signs of abdominal pain — pacing, restlessness or yelping when touched
A bad reaction to medication — don’t hesitate to get support.
Remember: you know your pup best. A quick call could be the first step to bringing back their bounce.
Veterinary diagnosis – the root cause of black stools
If your vet suspects melena or another cause behind black stools, they may take the following diagnostic steps:
Physical examination: Checking for signs of pain, bloating, or dehydration.
Faecal analysis: Identifying parasites, bacteria, or blood.
Blood tests: A complete blood count, chemistry panel, and clotting profile may be required to help assess organ function, clotting ability, signs of infection or anaemia.
Diagnostic imaging: X-rays or ultrasounds can detect internal bleeding or blockages.
Endoscopy or biopsy: My be used to explore your pup’s GI tract to identify the problem.
Early diagnosis makes a big difference. Don’t wait if you’re concerned.
How a fresh food diet can help
Your dog’s gut health plays a powerful role in their overall wellbeing — and what’s in their bowl can make a difference. A complete and balanced diet made with real food supports healthy digestion and may reduce the risk of some of the issues that can lead to black stools.
Here’s how:
Better nutrient absorption: Fresh, gently cooked meals retain more of their natural nutrients, supporting gut health and healthy bowel movements.
Supports a balanced microbiome: A healthy microbiome may reduce the risk of digestive upsets.
Keeps their gut lining strong: Real food packed with antioxidant and anti-inflammatory properties, essential vitamins and minerals can help maintain a healthy gut lining — reducing the risk of bleeding caused by ulcers or inflammation.
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Other ways to prevent the causes of black dog poo
Proactive health care is a great approach to supporting your dog’s digestive wellbeing.
Avoid unsupervised scavenging: teach a solid ‘leave it’ command and be mindful in high-risk areas.
Use medications as directed: only give NSAIDs and supplements under veterinary guidance and supervision.
Parasite prevention: Talk to your vet about a tailored parasite prevention plan.
Monitor their health: Small changes in their poo can signal bigger health issues. Keep an eye on the quality, colour, and consistency of their stools, and watch for other signs and symptoms.
Support their gut with prebiotics and probiotics: Support your dog’s gut health with probiotics like Lyka’s Go-To Gut Helper, and prebiotic dietary fibre to nourish their gut microbiome.
Lyka: the real food difference for your dog
Finding black stools might feel alarming, but many causes are treatable and preventable. With real, nourishing food and regular check-ups, you’ll be giving your pup the best chance to live their healthiest, happiest life.
Lyka’s range of meals are made with over 50 real food ingredients, featuring five proteins and nutritious veggies — giving your dog variety and optimal nourishment every day.
That’s the real food difference.
