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Change in bowel habits: when to see a GP

Published 13 March 2026 ·Last reviewed 13 March 2026 by the editorial team ·How we create our content

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.

Common questions

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.

What will the GP do?

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.

When to seek care Heavy bleeding or feeling faint? Get emergency help now. Emergency: 911

Not sure how urgent it is? Get help today.

  1. Emergency

    Heavy bleeding, black tarry stools, feeling faint, severe pain or trouble breathing.

    Call 911 or go to the ER.

  2. Today

    Fever, pain getting worse, a hot swollen lump, or trouble passing urine.

    Call your doctor or go to urgent care.

  3. Soon

    Bleeding or bowel changes nobody has checked, or anything lasting 3 weeks.

    Book a doctor’s appointment.

Feeling overwhelmed? Call or text 988, any time.

See all the signs

For this topic, get medical advice if you notice:

  • Unexplained change in bowel habits lasting more than three weeks
  • Change accompanied by rectal bleeding, weight loss, or fatigue
  • New constipation or diarrhoea in someone over 40
  • Severe abdominal pain with altered bowel function

Recording how you feel is not the same as being checked. These are the signs that need a doctor’s attention.

Call 911 or go to the emergency room now if you have:

  • bleeding that will not stop, a lot of blood (the toilet water turns red, or you pass large clots), or any bleeding with feeling faint or dizzy
  • fainting, a racing heart or trouble breathing
  • confusion or slurred speech, extreme shivering, no urine in a day, or blotchy skin
  • sudden severe belly pain, or a swollen, hard belly with vomiting or not passing stool or gas
  • you cannot pass urine at all, or your bladder feels full and painful and you can’t empty it
  • redness, swelling or severe pain spreading quickly around your anus, genitals or groin, especially with a fever or feeling very ill
  • a fever with a painful swelling near your anus if you have diabetes or a weakened immune system (for example, from chemotherapy or transplant medicines)
  • black, tarry stools

Call your doctor or go to urgent care today (or the ER if you can’t be seen today) if you have:

  • a temperature of 100.4°F (38°C) or higher, chills, vomiting, or feeling generally unwell
  • pain that is getting worse over days, or severe pain that stops you sitting or sleeping
  • a hot, swollen or very tender lump near your anus or at the top of the crease between your buttocks, or foul-smelling discharge
  • trouble urinating
  • bleeding that is getting heavier or more frequent, or blood mixed into your stool
  • feeling much more tired than usual, looking pale, or getting out of breath more easily than you used to
  • not passing stool for several days, or new belly pain

Make an appointment with your doctor if:

  • you have never had these symptoms checked by a doctor or nurse — whatever your age
  • you have had rectal bleeding for more than 3 weeks
  • your bowel movements have been looser, thinner or more frequent than usual for 3 weeks or more, or you have lost weight without trying
  • symptoms have not settled after a week or so, or keep coming back
  • you notice a new lump near your anus, between your buttocks or in your belly, or an itch or discharge that does not clear
  • you have new leakage or trouble controlling your bowels
  • you are 45 or over, or have a family history of bowel cancer or inflammatory bowel disease, and any of these symptoms are new for you

If you are unsure, it is always reasonable to ask. If things feel overwhelming, call or text 988 (Suicide & Crisis Lifeline) or chat at 988lifeline.org, any time. If you don’t feel safe, call 911.

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Pain during bowel movementsSpasm or crampingConstipationIncomplete evacuationUrgency

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