Bowel habits vary from person to person. However, sudden changes can indicate an underlying health condition, such as irritable bowel syndrome (IBS) or inflammatory bowel disease (IBD).

For some people, having one bowel movement a day is normal. For others, having several bowel movements a day or one every 2 days is normal. There is no set healthy pattern.

However, significant changes in the frequency or the appearance can indicate a problem, particularly when these changes occur with other issues, such as diarrhea, constipation, or abdominal pain.

This article investigates what can cause changes in bowel movements and when to see a healthcare professional. It also describes how doctors reach a diagnosis and the treatments.

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This long-term health condition affects the digestive system. The medical community is still unsure of the exact causes, but digestive problems and increased sensitivity within the gut may be involved.

People with IBS experience a range of digestive symptoms, including:

  • abdominal cramps and pain
  • diarrhea
  • constipation
  • bloating
  • gas

Crohn’s disease is a type of IBD. It can cause inflammation in any part of the digestive tract, but it most commonly affects the small intestine and the start of the large intestine, or colon.

Crohn’s is generally a lifelong condition, and its symptoms can include:

  • diarrhea
  • abdominal cramps and pain
  • bloody stools
  • fatigue
  • sudden urges to have a bowel movement
  • constipation
  • weight loss

Ulcerative colitis is another type of IBD, and it also tends to last a lifetime. It causes inflammation and ulcers to develop along the lining of the colon and rectum.

Symptoms of ulcerative colitis can include:

  • diarrhea
  • stools that contain blood or mucus
  • abdominal cramps or pain
  • strong, frequent urges to have a bowel movement
  • fatigue
  • weight loss
  • anemia

The thyroid gland releases hormones to control a range of processes in the body, including growth and metabolism.

Hypothyroidism involves the thyroid not producing enough hormones, or being “underactive.”

In addition to constipation, hypothyroidism can cause:

  • fatigue
  • sensitivity to temperature
  • lethargy
  • weight gain
  • dry skin

Celiac disease is also a lifelong condition. It occurs when gluten in the diet causes digestive problems. Gluten is a type of protein in wheat, rye, and barley.

According to the National Institute of Diabetes and Digestive and Kidney Diseases, around 2 million people in the United States have celiac disease, and many are unaware of it.

Doctors are unsure what causes this condition, but they believe that it stems from a problem with the immune system. It can sometimes run in families.

Symptoms of celiac disease can include:

  • diarrhea
  • abdominal cramps and pain
  • bloating
  • upset stomach
  • constipation
  • gas

Colon, rectal, and colorectal cancer are types of bowel cancer. The name describes where the cancer first develops.

Symptoms of bowel cancer can include:

  • blood in stools
  • persistent changes in bowel habits, such as diarrhea or constipation
  • abdominal pain or cramps
  • rectal bleeding
  • the urge to have a bowel movement, even after having one
  • bloating
  • fatigue and weakness
  • weight loss

It is important to note that many less severe health conditions can cause these symptoms. In most cases, the cause is something other than cancer.

Seek professional guidance if any change in bowel movements has persisted for more than a few days. Even minor changes, such as constipation or diarrhea, can indicate a health issue.

If more severe symptoms occur, consult a healthcare professional immediately. These can include:

  • blood, mucus, or pus in stool
  • severe abdominal cramps or pain
  • severe diarrhea that lasts more than a day
  • dizziness or confusion
  • persistent nausea or vomiting

First, a healthcare professional reviews a person’s symptoms and medical history. This also involves asking about the frequency and consistency of bowel movements.

They may need a blood or stool sample. For example, a blood test can indicate inflammation or help rule out certain diagnoses.

The healthcare professional may also request:

  • Imaging tests: These might include X-rays, CT scans, and ultrasounds. They can help show irregularities and signs of damage in the internal organs.
  • Fecal immunochemical testing: This is a noninvasive screening for colon disease. A healthcare professional collects and tests a sample of stool.
  • An endoscopy: This involves inserting a thin tube with a light and camera attached down the throat and into the digestive tract to look for signs of a health problem.
  • A colonoscopy: This involves inserting a thin tube with a light and camera attached into the rectum to check for problems along the colon.
  • A sigmoidoscopy: This involves inserting a thin tube with a light and camera attached into the rectum to check for problems with the sigmoid colon, the section closest to the rectum.

The best approach depends on the cause of the bowel changes. If no cure is available, the treatment aims to relieve the symptoms and prevent the health issue from worsening.

Treatment plans may involve:

  • dietary and other lifestyle changes
  • courses of medication, which may include anti-inflammatory, immunosuppressant, or anticancer drugs
  • surgery

Everyone’s bowel habits are different, and temporary changes are usually nothing to worry about.

However, persistent or severe changes can indicate an underlying health problem, especially when additional symptoms occur. IBS, IBD, thyroid problems, celiac disease, and cancer can all cause persistent bowel issues.

If bowel-related changes last for more than a few days, contact a healthcare professional. Seek immediate medical attention for severe symptoms, such as blood or mucus in stools, intense pain or cramping, or persistent nausea or vomiting.