What counts as a change in bowel habits?

A change in bowel habits is any persistent alteration from your normal pattern — new constipation, new diarrhoea, alternating between the two, changes in stool form or frequency, increased urgency, or a persistent feeling of incomplete emptying. The key word is persistent — lasting more than three weeks and not explained by an obvious cause.

Is a change in bowel habits always serious?

No. Most changes in bowel habits are caused by common, benign factors — diet, stress, medication, travel, or conditions like IBS. However, a persistent, unexplained change warrants assessment because it can occasionally be a sign of more significant conditions, including inflammatory bowel disease or, rarely, bowel cancer.

At what age should I be more concerned?

While changes in bowel habits should be assessed at any age if persistent, the threshold for investigation is typically lower in people over 40 to 50, particularly if the change is accompanied by other symptoms. National screening programmes and GP referral guidelines reflect this increased awareness.

Your GP will typically take a detailed history, examine your abdomen, and may perform a digital rectal examination. They may arrange blood tests and stool tests (including a faecal calprotectin test to check for bowel inflammation). Depending on the findings, they may refer you for further investigation such as colonoscopy.

Change in bowel habits: when to see a GP

At a glance

A change in bowel habits — new constipation, new diarrhoea, altered frequency, or a persistent change in stool form — is one of the symptoms that health guidelines consistently say should be assessed if it persists for more than three weeks.

Most of the time, the cause is common and benign. But persistent, unexplained changes warrant a medical conversation to rule out conditions that benefit from early identification.

What counts as a change

Everyone’s bowels are different. What matters is a change from your personal normal:

You were regular and are now frequently constipated
You were rarely loose and now have frequent diarrhoea
You alternate between constipation and diarrhoea in a new pattern
Your stool has changed in form — thinner, harder, looser, or different in appearance
You have new urgency — needing to rush to the toilet
You feel like your bowels do not empty completely
You are going significantly more or less often than your usual pattern

The change needs to be persistent — at least three weeks — and not clearly explained by something obvious (a stomach bug, travel, a new medication, a significant dietary change).

Common causes

Benign and very common

Diet changes: increased or decreased fibre, new foods, irregular eating
Stress and anxiety: the gut-brain connection is strong and well-documented
Medication: many medications affect bowel function, including antibiotics, iron supplements, antidepressants, and pain medication
Travel: disruption to routine, diet, and time zones
IBS (irritable bowel syndrome): a very common functional condition that causes chronic changes in bowel habits

Less common but important to identify

Inflammatory bowel disease (IBD): Crohn’s disease and ulcerative colitis
Thyroid disorders: can affect bowel motility
Coeliac disease: gluten sensitivity affecting the bowel
Infections: persistent infections that need treatment

Rare but serious

Bowel cancer: a persistent, unexplained change in bowel habits — especially in people over 40 — is one of the recognised warning signs. It is uncommon, but early identification improves outcomes significantly.

When to see your GP

Definitely see a GP if

The change has lasted more than three weeks and is not explained
The change is accompanied by rectal bleeding
You have unexplained weight loss
You have persistent abdominal pain or bloating
You are over 40 with a new, unexplained change
There is a family history of bowel disease or bowel cancer
You have fatigue alongside the bowel change
There is blood or mucus in the stool

Consider seeing a GP if

You are not sure whether the change is significant
You are worried — persistent anxiety about your symptoms is itself a reason to seek assessment
The change is affecting your quality of life

What to expect at the appointment

History

Your GP will ask about:

What has changed and when it started
Your previous bowel habits (your normal)
Associated symptoms — pain, bleeding, weight, appetite, energy
Medications and supplements
Family history
Diet and lifestyle

Examination

Abdominal examination — feeling for tenderness or masses
Digital rectal examination — may be performed to check for abnormalities

Investigations

Depending on the history, your GP may arrange:

Blood tests: full blood count, inflammatory markers, thyroid function, coeliac screen
Stool tests: faecal calprotectin (to check for bowel inflammation), stool culture (to check for infection)
Referral for further investigation: colonoscopy, flexible sigmoidoscopy, or CT colonography

The practical message

A change in bowel habits is very often caused by something common and manageable. The purpose of getting it checked is not to look for something terrible — it is to identify the cause early and manage it appropriately. One GP appointment can set the process in motion, and for most people, the outcome is reassurance and a clear plan.

Do not ignore a persistent change because you are worried about what it might be. The earlier conditions are identified, the better the outcomes — for both common conditions and the rare serious ones.