Posted by Stephen Crowther
on April 30, 2026
Stool colour is the second thing every UK vet checks on a faecal sample, right after form. And it's the single home observation that tells an owner most about whether their dog is “fine, just fine” or “ring the practice this morning”.
This guide is the UK colour chart your vet would walk you through in a consultation. We cover every common shade — brown, yellow, orange, green, white or grey, black, and red — what each one usually means, what's an emergency, and what to do next.
See it on your dog's last poo. Snap a photo and run it through the Superwild Poop Inspector. The tool reads colour, form, and consistency in one go and gives you a Gut Score plus tailored next steps. Free, no email needed.
Healthy dog poop colour: what to expect
A healthy dog stool sits somewhere between milk-chocolate brown and dark chocolate brown. The colour comes from bilirubin and stercobilin — pigments produced when red blood cells break down and pass through the liver and gallbladder into the gut. As long as those processes are working normally, brown is what comes out.
Two notes before we go through the abnormal colours.
First, diet shifts the baseline. A dog on a beef-based food will produce darker stools than one on chicken or fish. Brands with a lot of beetroot or sweet-potato can tint reddish-brown. A single odd-coloured poo, in an otherwise bright dog, that you can trace to a treat or a new food, is rarely an emergency.
Second, persistence and pattern matter more than a single instance. UK vets generally start to take a colour change seriously when it lasts more than 48 hours, or when it shows up alongside any other symptom — vomiting, lethargy, going off food, straining, or visible distress.
Yellow or mustard-coloured dog poop
Yellow is not a natural colour for dog stool. According to UK guidance from VetUK and the Pet Health Club, yellow or mustard-toned poo most often indicates gut inflammation, food intolerance, or a problem with bile flow.
Common causes:
- Recent diet change — the most common reason. Switching food too quickly is the textbook trigger.
- Food allergy or intolerance — chicken, beef, dairy, and grain sensitivities can all produce yellowish stools.
- Giardia or other parasites — yellow, sometimes greasy stools with a strong smell are classic signs.
- Liver, gallbladder, or pancreatic issues — less common, but more serious.
What to do: if your dog is otherwise well and you've recently changed food, hold the new food, return to the previous one, and watch for 48 hours. If yellow stools persist past two days, occur alongside vomiting, or your dog seems lethargic, contact your vet.
Orange dog poop
Orange usually points the same way as yellow — bile-flow issues, gallbladder, or rapid transit through the gut. UK vets often see orange stools in dogs with mild liver upset or following a fatty meal that overwhelmed digestion. If it's a one-off and your dog is fine, monitor. If it's persistent or paired with vomiting, jaundice, or lethargy, ring your practice the same day.
Green dog poop
Green has the widest range of explanations on the chart, and most are benign. The PDSA notes that the most common cause of green dog poo is eating grass. Many dogs do this for fibre, settling an upset stomach, or simply because they enjoy it.
Less benign causes:
- Gallbladder problems — bile is dark green; an inflamed gallbladder can release more pigment than normal.
- Intestinal parasites — particularly Giardia.
- Rat poison or rodenticide exposure — many UK rodenticides contain green dye specifically to make accidental ingestion easier to spot. This is an emergency. Contact a vet or the Animal PoisonLine immediately if you suspect any toxin exposure.
White, grey, or chalky dog poop
White or grey stools are unusual and almost always indicate a problem with fat absorption or bile. The Royal Veterinary College and UK first-opinion practices typically investigate three angles:
- Exocrine pancreatic insufficiency (EPI) — the pancreas isn't producing enough digestive enzymes. Stools become pale, greasy, voluminous, and foul-smelling. Common in German Shepherds and a handful of other breeds.
- Bile duct obstruction — without bile, stool loses its brown colour. May be paired with jaundice.
- High-bone or high-calcium diet — raw feeders sometimes see chalky white stools when the bone-to-meat ratio is too high.
Black or tarry dog poop
Black, tarry stools have a specific clinical name — melaena — and they are the most urgent colour on the chart. Black colouring comes from digested blood, which means bleeding higher in the digestive tract: the stomach, oesophagus, or small intestine.
Causes that UK vets see most often: gastric ulcers (often NSAID-related), foreign-body trauma to the stomach lining, bleeding tumours, coagulation disorders, severe parasite burdens.
What to do: contact your vet the same day. Melaena is rarely an isolated symptom — your dog may also be off food, lethargic, vomiting, or pale at the gums. Don't wait to see if it resolves.
When to see a vet — black or red stools
Treat any of the following as a same-day vet call, ideally within hours:
- Black, sticky, tarry stools (melaena — digested blood from upper GI)
- Fresh red blood streaks or clots in stool (haematochezia — lower GI bleed or colitis)
- Dark red, jam-like stools especially with vomiting or lethargy (possible AHDS — see our diarrhoea emergency guide)
- Pale gums, weakness, or rapid breathing alongside any of the above
If your usual UK practice is closed, the BVA's Find a Vet directory and Vets Now out-of-hours service can locate emergency cover.
Red, blood-streaked, or pink dog poop
Red is fresh blood — haematochezia in clinical terms — and it usually means bleeding lower in the digestive tract: the colon, rectum, or anus. The PDSA notes haematochezia is one of the most common owner-reported reasons for an urgent vet visit.
Causes: colitis (large-bowel inflammation, often with mucus and straining); anal gland issues (small streaks of blood on otherwise normal stool); rectal polyps or masses (older dogs especially); Acute Haemorrhagic Diarrhoea Syndrome (AHDS) (sudden, profuse, jam-like bloody diarrhoea, sometimes with vomiting; an emergency); parvovirus (particularly in unvaccinated puppies).
Mucus, jelly, or worms in dog poop
Not strictly a colour, but worth covering. A small glistening film of mucus is normal. Jelly-like coatings, especially with red streaks, indicate large-bowel inflammation. Visible worms — either short rice-grain segments (tapeworm) or longer pasta-shape worms (roundworm) — mean it's time for a worming treatment and a vet conversation.
UK colour decision tree
| Colour | Likely cause | Action |
|---|---|---|
| Chocolate brown | Healthy | Monitor |
| Yellow / mustard | Diet change, intolerance, parasites, bile-flow | Vet if persistent >48h |
| Orange | Bile/gallbladder, fatty meal | Vet if persistent or jaundice |
| Green | Grass, parasites, gallbladder, rodenticide | Vet if persistent or toxin suspicion |
| White / grey | EPI, bile obstruction, too much bone | Vet visit |
| Black / tarry | Upper GI bleed | Same-day vet |
| Red streaks | Colitis, anal gland, polyps, AHDS, parvo | Vet — same-day if profuse |
A simple home routine
Once a week, glance properly at form, colour, and any inclusions when you pick up. If everything looks like log-shaped milk-chocolate brown, you're done. If something is off, photograph it and note the date.
For more detail on stool form, see our complete UK guide to the Bristol Stool Scale for dogs. For frequency norms, see how often should a healthy dog poop. For diarrhoea emergencies, see when dog diarrhoea is an emergency vs not.
How daily nutritional support fits in
For dogs whose stools are consistently off-colour without an obvious cause, UK vets often suggest stabilising the underlying nutrition first. Super Everyday is Superwild's vet-developed daily powder, designed to support the seven pillars of canine wellness — including gut health and bile-flow support — across the lifespan. It is not a treatment for any specific condition; it is a daily nutritional foundation.
Quick action. Use the Superwild Poop Inspector to scan your dog's next poo for an instant colour-and-form reading. For the full 7-pillar wellness picture, take the Super Score quiz. And for ongoing daily nutritional support, Super Everyday is the foundation we recommend.
Frequently asked questions
What colour should healthy dog poop be?
Healthy dog poop should be a chocolate-brown colour, ranging from milk-chocolate to dark-chocolate depending on diet. Any persistent shade outside that range is worth investigating, particularly if it lasts more than 48 hours or appears alongside vomiting, lethargy, or off food.
Why is my dog's poop yellow?
Yellow dog poop in the UK most often points to a recent diet change, a food intolerance, gut inflammation, or a bile-flow issue. If it's a one-off and your dog is otherwise well, return to the previous food and monitor for 48 hours.
Is black dog poop always an emergency?
Black, sticky, tarry dog poop (melaena) is one of the more urgent signs on the colour chart and warrants a same-day call to your vet. It indicates digested blood from the upper GI tract.
Why is my dog's poop green?
The most common cause of green dog poop is eating grass. Other possibilities include intestinal parasites, gallbladder issues, or exposure to rodenticide, which is often dyed green in the UK.
When should I take a poop sample to the vet?
UK vets recommend bringing a fresh stool sample whenever your dog has had persistent colour changes, diarrhoea, blood in stool, or visible worms or mucus. The PDSA recommends a sample less than 12 hours old, sealed in a clean container.
Last updated April 2026. This guide is intended for general information and does not replace advice from a UK-registered MRCVS veterinarian.
