Irregular Bowel Movements

Most people have an idea of what their usual bowel pattern is, including the frequency and consistency (e.g. I move my bowel once very morning and stool is soft and formed). Constipation and diarrhea are commonly used terms to generalize abnormal bowel pattern. But what is "normal"? In general, normal bowel pattern refers to:

  • Having a bowel movement at least once every 3 days, but not more than 3 bowel movements per day.

  • Stool should pass easily and does not require straining

  • You should feel complete evacuation after your bowel movement

As food passes through your gastrointestinal tract and comes out of the end as feces, intestinal fluid including digestive enzymes are secreted into the stomach and small intestine, nutrients are being absorbed mostly by small intestines, and water and electrolytes are absorbed by the large intestine. In general, the longer the stool stays in the colon, the more fluid is reabsorbed and the drier and harder the stool becomes. Diarrhea occurs when the fecal waste travels through the GI tract quickly and much of the intestinal fluids are not reabsorbed. Some disease processes damage the intestinal lining (mucosa) that normally absorbs the fluid, or stimulate the intestine to secrete more fluid than usual, thus causing diarrhea. Bowel movement is the result of complex processes involving interaction of your intestinal cells with the food, coordination of intestinal peristalsis and anorectal and pelvic floor muscle function. These in turn are affected by the nerves, chemicals, hormones, and other factors such as bacteria in your intestine. A deviation from the norm of any one of the above may result in irregular bowel movements, which can be alternating diarrhea, constipation or both.

Some causes of irregular bowel movements
  • Irritable bowel syndrome (IBS)

  • Small intestinal bacterial overgrowth (SIBO)

  • Food sensitivity or intolerance, such as intolerance to lactose in dairy, gluten in certain grain, or high fat food

  • Mechanical obstruction of the intestine - such as with cancer or stricture

  • Inflammation of the intestinal lining - such as in Crohn's disease or ulcerative colitis

What is IBS?

Irritable bowel syndrome, commonly known as IBS, is a functional disorder of the GI tract. It means there is no detectable anatomical or structural abnormality (all the tests are normal) but the bowel is not functioning normally. Some symptoms of IBS include:

  • Abdominal pain, cramp, gas or bloating

  • Abdominal discomfort is usually relieved with bowel movement

  • Change in bowel pattern, alternating between constipation and diarrhea

The exact cause of IBS is not known. Diagnosis of IBS is made after tests such as labs and endoscopy are done to exclude the presence of other abnormality or disease process.

What is small intestinal bacterial overgrowth (SIBO)?

SIBO is a condition in which there is excessive bacteria in the small intestine. The exact cause is not known, but it was thought to be associated with previous stomach or intestinal surgery, slow GI motility, and prolonged antibiotic use. Typical symptoms include:

  • Chronic diarrhea

  • Abdominal pain, gas or bloating

  • Nausea and decreased appetite

  • Malabsorption and weight loss

There are specific tests for SIBO, however these tests are not readily available and not cost effective. Typically the condition is treated primarily with oral antibiotics. Rarely a surgically correctible cause is found and amenable to surgery.

When should you be concerned about your bowel irregularity?

You should pay attention to any change in your usual bowel pattern, i.e. you were previously "normal" or "regular" but something changed recently, especially when your irregularity comes with other symptoms such as blood in stool or when wiping, pain in the abdomen or anorectal region, abnormal discharge from anorectum, weakness or weight loss, you should seek medical attention promptly. Sometimes you may be able to pinpoint certain food in your diet as the source. When you are not sure or when you just don't feel right about moving your bowel, it is time to bring it up to your doctor.

Helpful links:


*American Society of Colon and Rectal Surgeons

**Cleveland Clinic