GP Explains What Your Poo Colour Reveals About Your Health—and When to See a Doctor

Your bowel movements can provide important clues about your overall health, diet, and even stress levels, says Dr Bhavini Shah, a GP at LloydsPharmacy Online Doctor. While there’s no “perfect” poo, understanding what the colour and texture of your stool indicate can help you spot potential health issues early.

What Your Stool Colour Means

Brown: This is the normal colour of healthy stool, signaling a functioning digestive system. If you see no other symptoms, there’s usually no cause for concern.

Green: Green stool often results from eating leafy greens, consuming green food dyes, or taking antibiotics. However, it can also indicate gastrointestinal conditions like gastroenteritis.
Yellow: Yellow stools may point to infections in the bowel or problems with the pancreas. Insufficient production or secretion of pancreatic enzymes can cause this colour change.
Grey/Pale: Pale, clay-coloured stools can signal issues within the biliary system—which includes the gallbladder, liver, and pancreas. Medications that treat diarrhoea may also cause grey stools. But importantly, this colour change can be linked to liver or pancreatic conditions, including blockages or tumours, both cancerous and benign.
Red: Bright red stool can be a sign of rectal bleeding, a symptom that must always be investigated promptly as it may indicate bowel cancer. Other warning signs include unexplained tiredness and weight loss. Any presence of blood in your stool should lead to a medical consultation.
Black: Black stool can result from certain medications, but it may also indicate internal bleeding in the stomach or issues like haemorrhoids. Medical advice should be sought to rule out serious problems.

What About Stool Shape and Texture?

A healthy stool typically looks like a smooth, sausage-shaped log, sometimes with small cracks on the surface. Constipation is defined by infrequent or hard stools that require straining. If you’re experiencing constipation, gradually increasing your dietary fibre to at least 30 grams per day can help. Fibre sources include oats, whole wheat pasta, beans, lentils, wheat bran, and linseed. Not only does fibre promote regularity, but it also reduces the risk of bowel cancer, heart disease, type 2 diabetes, and stroke.

Eating a balanced diet including fruits high in sorbitol—such as apples, apricots, grapes, raspberries, and strawberries—along with drinking plenty of water and avoiding excessive alcohol, is also recommended.

On the other hand, watery stools without solid pieces suggest diarrhoea. While this often resolves on its own, it can be a sign of infections caused by viruses, bacteria, or parasites, especially if linked to contaminated food or water. Staying hydrated and replenishing lost fluids, sugars, salts, and minerals is crucial during bouts of diarrhoea.

When to See a GP

You should consult a doctor if you notice: