10 Common Causes of a Change in Bowel Habits

A change in bowel habits (such as changes in frequency or stool consistency) can happen for all sorts of reasons. You might feel constipated after a day of traveling, for example, or experience diarrhea when you're especially stressed. Gastrointestinal disorders like celiac disease and ulcerative colitis can also affect bowel habits—as can serious conditions like colon cancer.

It's worth knowing that there's no single healthy pattern. For some people, one bowel movement a day is normal; for others, several a day or one every couple of days is typical. What matters more is a shift from your own usual pattern, especially when it lasts or comes with other symptoms. So what could be the reason for a change in bowel habits you may be experiencing? Here we'll cover some common causes—including lifestyle factors and health conditions—so read on.

Traveling and changes to your schedule can cause altered bowel habits, especially if you're not getting adequate water (which can be especially common on long drives or flights).

Physical activity can affect bowel habits, and if you're experiencing constipation it may be because you aren't exercising as frequently as you used to.

When consumed in large amounts, dairy products can lead to a change in bowel habits.

Stress and anxiety can disrupt many processes in the body—and that includes the gastrointestinal system. So whether you're experiencing constipation or diarrhea, it could have something to do with stress or anxiety.

Overusing laxatives can weaken bowel muscles over time and trigger a change in bowel habits.

Certain medications like antidepressants, iron supplements, and opioids can also affect your bowel—as well as antacid medicines that contain aluminum or calcium.

Resisting the urge to have a bowel movement can lead to constipation later on.

It's normal to experience a change in bowel habits when you're pregnant. Constipation is relatively common during pregnancy and may be due to shifts in hormone levels and lowered fluid intake and fiber consumption.

In addition to the factors discussed above, gastrointestinal disorders can also lead to a change in bowel habits.

Irritable bowel syndrome, or IBS, can cause the small and large intestine (the colon) to contract more often. Symptoms can include:

• Diarrhea, constipation, or both

• Harder, looser, or more urgent stools

• Abdominal pain and cramps

• Bloating and excess gas

Symptoms often come and go, and many people notice patterns in what brings on an IBS flare-up.

Ulcerative colitis is an inflammatory bowel disease. It causes prolonged inflammation and sores, or ulcers, in your digestive tract. Symptoms vary but can include:

• Diarrhea, often with blood or mucus

• Increased urgency to have a bowel movement

• Constipation

• Abdominal cramps or pain

• Fatigue and weight loss

Crohn's disease is another inflammatory bowel disease that causes inflammation in the digestive tract. It most commonly affects the small intestine and the start of the colon, and symptoms can include:

• Severe diarrhea

• Abdominal cramps and pain

• Bloody stools

• Sudden urges to have a bowel movement

• Constipation

• Fatigue and weight loss

Celiac disease is an immune system reaction to eating gluten, a protein commonly found in wheat, barley, and rye. This immune response may cause a change in bowel habits along with other digestive symptoms:

• Diarrhea or constipation

• Abdominal cramps and pain

• Bloating and gas

• Upset stomach

Your thyroid gland releases hormones that help regulate a wide range of processes in the body, including metabolism—and digestion is part of that. When thyroid hormone levels run low, everything can slow down, constipation included.

Hypothyroidism is the term for a thyroid that isn't producing enough hormone. Alongside constipation, signs of an underactive thyroid can include:

• Fatigue and lethargy

• Sensitivity to cold

• Weight gain

• Dry skin

An overactive thyroid can have the opposite effect, leading to more frequent bowel movements or looser stools.

A change in bowel habits may also be connected to colon cancer. Risk increases with age, though cases among younger adults have been rising. The type of bowel habit change can differ from person to person (and colon cancer doesn't always affect bowel habits), but more frequent bowel movements or looser stools—or both—are especially common. More rarely, narrow, "pencil-thin" stool can also occur. Keep in mind that many far less serious conditions cause these same symptoms, and in most cases the cause is something other than cancer. Routine screening for colon cancer is recommended starting at age 45 for people at average risk, and you can screen from home with the Everlywell FIT Colon Cancer Screening Test if you're due.

If a change in your bowel habits has stuck around for more than a few days, it's worth checking in with a healthcare professional—even a seemingly minor change like ongoing constipation or diarrhea can point to something treatable.

Some symptoms warrant prompt medical attention. Reach out right away if you notice:

• Blood, mucus, or pus in your stool

• Severe abdominal cramps or pain

• Severe diarrhea lasting more than a day

• Dizziness or confusion

• Persistent nausea or vomiting

• Unexplained weight loss

A healthcare provider will typically start by reviewing your symptoms and medical history, including how often you're having bowel movements and what your stool looks like. From there, they may order a blood or stool sample—for example, a blood test can point to inflammation or help rule certain conditions out.

Depending on your symptoms and risk factors, they may also recommend:

• Imaging tests – X-rays, CT scans, and ultrasounds can reveal irregularities or signs of damage in the internal organs.

• Fecal immunochemical testing – A FIT test is a noninvasive stool screening that checks for hidden blood in the stool.

• An endoscopy – A thin tube with a light and camera is passed down the throat and into the digestive tract to look for problems.

• A colonoscopy – A thin tube with a light and camera is inserted into the rectum to check the length of the colon.

• A sigmoidoscopy – A similar scope checks the sigmoid colon, the section closest to the rectum.

How a change in bowel habits is treated depends entirely on what's behind it. For lifelong conditions like IBD or celiac disease, the goal is managing symptoms and preventing flare-ups rather than curing the condition. Treatment plans may involve:

• Dietary and lifestyle changes – Adjusting fiber and fluid intake, moving more, and keeping a food journal to spot patterns between what you eat and how you feel

• Medication – Anti-inflammatory drugs, immunosuppressants, thyroid hormone replacement, or other prescriptions, depending on the diagnosis

• Surgery – Reserved for cases where other treatments haven't worked or the underlying condition requires it

There's no single "normal" when it comes to bowel habits—what's typical varies from person to person, and shifts in frequency or stool consistency are usually short-lived. Travel, stress, a new medication, a change in how much fiber or water you're getting, or a food that doesn't agree with you can all account for it, and things tend to settle once the cause passes.

What's most useful is knowing your own baseline so you can tell when something has genuinely changed, and building in habits that support your colon health along the way. If a change sticks around, keeps coming back, or comes with symptoms like pain, blood, or unexplained weight loss, bring it up with your healthcare provider—they can help you pinpoint the cause and figure out whether any testing makes sense.