When to see a doctor about your poo

Updated 15 October 2026 5 min read By the Poochievements editorial team

Most poo changes are harmless and short-lived. A few are worth getting checked — and catching them early matters. Here’s the clear list.

Call 999 or go to A&E if you are passing a lot of blood, feel faint or dizzy, are vomiting blood, have sudden severe tummy pain, or your tummy is hard and swollen. In the UK you can also call NHS 111 for urgent advice.

See your GP if you notice

Blood in your poo — bright red or darker. It is often from piles or a small tear, but it is also a main symptom of bowel cancer, so always get it checked.
Black, sticky, tar-like stool — can mean bleeding higher in the gut. Seek advice promptly. (Iron tablets, bismuth medicines and liquorice can also turn stool black.)
Pale or clay-coloured stool — may mean bile isn’t reaching the gut; urgent if your skin or eyes turn yellow.
A change in bowel habit lasting several weeks — especially looser, more frequent stools.
Tummy pain, a lump in your tummy, or bloating that won’t go away.
Unexplained weight loss or extreme tiredness (which can be a sign of anaemia).
Diarrhoea lasting more than 7 days, or constipation not improving with self-care.

Bowel cancer: the key facts

Bowel cancer is one of the most common cancers in the UK and women have the same risk as men. The main symptoms are blood in your poo, changes in bowel habit, tummy pain, unexplained weight loss and anaemia. Smoking, heavy drinking, obesity and a poor diet increase risk. Bowel screening kits look for hidden blood — if you’re sent one, use it.

What happens at the GP

Your GP will ask about your symptoms, diet, medicines and family history, and may gently examine your bottom. They are very used to this — you can ask for a chaperone or a doctor of a particular sex. Bringing a clear record helps enormously: Poochievements can generate a printable doctor report with your stool types, colours, symptoms and flagged entries.

Frequently asked questions

Is blood in poo always serious?

Not always — piles and small tears are common causes — but it is a main symptom of bowel cancer, so you should always get it checked by a GP.

What does black poo mean?

Black, tarry stool can indicate bleeding in the upper digestive tract and needs prompt medical advice. Iron supplements, bismuth medicines and liquorice can also darken stool.

Sources

This guide is for general education and is not a substitute for advice from your doctor. If you are worried about symptoms, contact your GP or NHS 111.