Changes in Bowel Habit (Diarrhea and Constipation)

Bowel habit refers to the frequency of passing stool. It varies among individuals but is considered normal if it is not more than three times a day and not less than three times a week. There are many other characteristics of bowel habit, like the time and trigger events. Some people have to pass stool first thing in the morning or a short time after eating a large meal.

What is bowel habit change?

A change in bowel habit refers to any variation in a person’s normal pattern of passing stool. Although this typically refers to the frequency of having a bowel movement, it can also extend to the consistency of the stool. For example, a person may suddenly experience very watery stool. While this is not a change in bowel habit as such most people do consider it to be an abnormality.

Strictly speaking, a change in bowel habit refers to passing stool too frequently or too infrequently when compared to a person’s normal bowel habit. At the two extremes are diarrhea and constipation. Diarrhea refers to passing stool more than three times in a day. Typically this is large volume of stool and often of a watery consistency. Constipation refers to passing stool less than three times weekly. The stool is typically hard and difficult to pass out.

Signs and Symptoms

Alterations in bowel habit is a symptom that may occur in various diseases. It may be accompanied by other symptoms include:

  • Bloating – a sensation of fullness in the abdomen.
  • Abdominal distension – swelling of the abdomen.
  • Excessive gas – either belching or flatulence.
  • Nausea and vomiting.
  • Abdominal pains and cramps.

With constipation there is the risk of complications like fecal impaction, while dehydration is the main complication seen with diarrhea. The symptoms of these conditions may therefore also be present at times.

Causes of Changes in Bowel Habit

There are a wide range of causes of constipation and diarrhea but the more common causes are discussed below. Usually it is caused by factors localized to the bowels but can sometimes arise with systemic conditions. Identifying the exact cause of diarrhea or constipation may at times require further investigations. Apart from specific causes that may cause diarrhea or constipation as mentioned below, certain conditions like colorectal cancer can cause either of these conditions.


  • Insufficient Water: Water is needed to move contents through the bowels. Stool is also softer and moves easily due to its water content. Therefore a lack of water intake or dehydration can lead to constipation.
  • Inadequate Fiber: Dietary fiber absorbs water and provides bulk to stool. It also softens stool. This bulk helps the contractions in the bowel to push the stool out during defecation.
  • Inactivity: People who live a sedentary lifestyle are more likely to experience constipation.
  • Functional Constipation: Occurs for no known reason and is believed to be due to a slowdown in normal bowel transit time – this is the time it takes contents to move from the mouth to the anus.
  • Bowel Blockage: An obstruction anywhere in the gastrointestinal tract may present with constipation as the bowel contents cannot pass beyond the blockage.
  • Hormone Problems: A number of hormonal disturbances can affect bowel habit and lead to constipation. This is mainly seen with pregnancy, hypothyroidism and diabetes.
  • Constipation-Predominant IBS: In irritable bowel syndrome (IBS) there is no disease that is causing the symptoms but instead it appears to be a disturbance in normal processes like movement through the bowel.
  • Nerve Problems: Since nerves coordinate movement through the bowels and defecation, any problem affecting these nerves can lead to constipation. It includes nerve problems like multiple sclerosis, Parkinson’s disease, autonomic neuropathy, spinal cord injury and stroke.
  • Muscle Problems: Disorders of the muscles that play a role in defecation can also lead to constipation. This is mainly seen with the pelvic muscles and the muscles of the anal sphincter that need to relax in order for stool to be passed out.


  • Infections: Gastrointestinal infections like infectious gastroenteritis (also referred to as food poisoning) and infectious enterocolitis are the most common causes of acute diarrhea.
  • Food Intolerance: Inability to digest or absorb certain nutrients can also lead to diarrhea. The most common food intolerance is the condition known as lactose intolerance, where the body cannot digest milk sugars (lactose) due to a deficiency of the enzyme lactase.
  • Inflammatory Bowel Disease (IBD): This is an autoimmune condition where the bowel becomes inflamed and ulcers form in the bowel wall.
  • Diarrhea-Predominant IBS: In irritable bowel syndrome (IBS) movement through the bowels is faster than normal and diarrhea occurs. There is no clearly identifiable cause of this condition.
  • Celiac Disease: In this condition the bowel walls react to the protein known as gluten which is found in wheat and related foods. This reaction may lead to symptoms like diarrhea.
  • Medication: Certain drugs can cause diarrhea as a side effect. One of the main drugs to do this is antibiotics which disturbs the bacterial content in the bowels thereby leading to antibiotic-associated diarrhea.
  • Surgery: Diarrhea may occur following surgery particularly with procedures like cholecystectomy where the gallbladder is removed.

Remedies for Bowel Habit Change

When diarrhea and constipation are due to an underlying medical cause then treatment needs to be directed at this condition. However, there are some simple dietary and lifestyle measures that can be useful in regulating bowel habit.

  • Eat foods that are high in fiber for at least one meal in a day.
  • Drink at least 2 liters of water daily. Oral rehydrating solutions are a better option for people with diarrhea.
  • Exercise regularly – at least 30 minute sessions at a time.
  • Eat several small meals rather than many large meals.
  • Probiotic yogurt may be useful for stabilizing the bowel bacteria.

It is important to not use laxatives or anti-diarrheal medication for long periods. These drugs only help relieve the symptoms like diarrhea and constipation momentarily. The root cause of diarrhea or constipation needs to be identified and treated accordingly. Continuous use of these drugs may worsen the symptoms and even lead to complications in the long term.

Please note that any information or feedback on this website is not intended to replace a consultation with a health care professional and will not constitute a medical diagnosis. By using this website and the comment service you agree to abide by the comment terms and conditions as outlined on this page