Your digestive system can tell you a surprising amount about what is happening inside your body. While occasional constipation, diarrhea, bloating, or abdominal discomfort is common, persistent or unusual changes in bowel habits should not automatically be dismissed as “just digestion.”

The colon, also known as the large intestine, plays an important role in absorbing water, processing waste, and forming stool. Problems affecting the colon can range from relatively minor conditions such as hemorrhoids or irritable bowel syndrome to inflammatory bowel disease, infections, diverticular disease, polyps, and colorectal cancer.

One important point is that symptoms alone cannot tell you exactly what is wrong. Many colon-related symptoms are nonspecific and can occur with several different conditions. In some cases, people with significant colon disease have few or no symptoms at all.

Still, knowing which changes deserve attention can help you recognize when it may be time to talk with a healthcare professional.

Here are six signs that may be associated with a possible colon problem.

1. A Persistent Change in Your Bowel Habits

One of the most noticeable signs of a digestive problem is a change in the way you normally have bowel movements.

This may include:

• New or persistent constipation

• Frequent diarrhea

• Alternating constipation and diarrhea

• Suddenly needing to use the bathroom much more often

• Feeling that your bowel movements have become unusually difficult

• A noticeable change in the consistency of your stool

• A change that continues for several weeks without an obvious explanation

Everyone's bowel habits are different. Some people naturally have bowel movements several times a day, while others may go every other day.

The important issue is a persistent change from your personal normal pattern.

For example, someone who has always had regular bowel movements but suddenly develops several weeks of diarrhea should pay attention to that change. Likewise, persistent constipation that does not improve with adequate fluids, fiber, movement, and other appropriate lifestyle measures deserves evaluation.

There are many possible causes, including dietary changes, medications, infections, stress, irritable bowel syndrome, thyroid disorders, inflammatory bowel disease, and colorectal conditions.

A change in bowel habits does not mean that you have cancer. However, if the change is persistent, unexplained, or accompanied by other symptoms, it is worth discussing with a healthcare professional.

2. Blood in Your Stool

Seeing blood when you use the bathroom can understandably be alarming.

Blood in or on the stool can come from several different sources. Bright red blood may occur with hemorrhoids or an anal fissure, particularly when associated with constipation or straining.

However, blood can also be associated with problems higher in the digestive tract, including colon polyps, inflammatory bowel disease, diverticular disease, and colorectal cancer.

The appearance of blood can vary.

You might notice:

• Bright red blood on toilet paper

• Blood coating the outside of the stool

• Blood mixed with stool

• Dark or very dark stools

• A change in stool color accompanied by other digestive symptoms

Not every instance of rectal bleeding indicates a serious disease. Hemorrhoids are extremely common, for example.

But one common mistake is assuming that bleeding is automatically caused by hemorrhoids without getting it evaluated—particularly when the bleeding is new, recurrent, or accompanied by other changes.

If you notice unexplained blood in your stool, especially if it keeps happening, speak with a healthcare professional.

Heavy bleeding, dizziness, fainting, weakness, or signs of significant blood loss require prompt medical attention.

3. Persistent Abdominal Pain or Cramping

Occasional stomach discomfort is extremely common. You may experience abdominal pain after eating too much, consuming certain foods, having gas, or experiencing temporary constipation.

The concern is when abdominal discomfort becomes persistent, recurrent, increasingly severe, or different from what you normally experience.

Colon-related conditions can sometimes cause:

• Cramping

• Lower abdominal discomfort

• A feeling of pressure

• Bloating associated with pain

• Pain related to bowel movements

• A persistent sensation of fullness

The location and character of abdominal pain can vary depending on the underlying condition.

For example, constipation can cause cramping and pressure as stool accumulates. Irritable bowel syndrome can cause abdominal pain associated with changes in bowel movements. Inflammatory conditions can produce abdominal pain along with diarrhea and other symptoms.

More serious conditions can also cause abdominal discomfort, but pain by itself is not enough to identify the cause.

Pay attention to patterns.

Does the pain repeatedly occur after eating? Does it improve after a bowel movement? Is it becoming more frequent? Is it accompanied by blood, fever, vomiting, weight loss, or changes in bowel habits?

Those details can help a healthcare professional determine what further evaluation may be appropriate.

4. Unexplained Changes in Stool Appearance

Your stool can naturally vary in color, size, shape, and consistency depending on what you eat, how much water you drink, medications, supplements, and how quickly food moves through your digestive system.

However, persistent unexplained changes deserve attention.

Some people notice that their stools have become consistently thinner, unusually narrow, harder, looser, or different in consistency.

A single narrow bowel movement is usually not a reason to panic. Temporary changes can occur because of constipation, diet, or changes in bowel movement patterns.

The concern is when a noticeable change continues.

You may also notice:

• Excessive mucus

• Stool that repeatedly appears unusually loose

• Persistent changes in stool consistency

• A sensation that stool is difficult to pass

• A feeling that you have not completely emptied your bowel

A persistent change does not necessarily indicate a colon tumor or cancer. There are many benign explanations.

Nevertheless, if your bowel movements remain noticeably different for an extended period—especially when combined with bleeding, abdominal pain, weight loss, or fatigue—medical evaluation is appropriate.

5. Unexplained Weight Loss or Persistent Fatigue

Sometimes the signs of a colon problem aren't directly related to the bathroom.

Unintentional weight loss can be one of the symptoms associated with a number of medical conditions, including some gastrointestinal diseases.

If you are losing weight without intentionally changing your diet, exercise routine, or calorie intake, it is worth finding out why.

Persistent fatigue is another symptom that should not automatically be blamed on being busy or not sleeping enough.

Certain colon conditions that cause chronic or microscopic blood loss can contribute to iron-deficiency anemia. Anemia may lead to symptoms such as:

• Fatigue

• Weakness

• Reduced exercise tolerance

• Shortness of breath with activity

• Dizziness or lightheadedness

• Pale skin in some people

• Headaches

Sometimes the amount of blood loss is too small to be visible in the toilet.

This is one reason unexplained iron-deficiency anemia—particularly in adults who are not expected to have a simple explanation for it—may lead doctors to investigate the gastrointestinal tract.

Again, fatigue and weight loss have countless possible causes. Stress, sleep problems, nutritional deficiencies, infections, hormonal conditions, medications, and many other illnesses can produce similar symptoms.

But persistent unexplained weight loss or fatigue should not simply be ignored.

6. A Persistent Feeling That You Need to Have a Bowel Movement

Another symptom that can sometimes be overlooked is a persistent sensation that you still need to have a bowel movement even after going to the bathroom.

This sensation is sometimes called tenesmus.

You may feel:

“I just went, but I still feel like I need to go.”

You might repeatedly return to the bathroom but pass only a small amount of stool.

Tenesmus can occur with several conditions, including inflammation of the rectum or colon, infections, inflammatory bowel disease, and other gastrointestinal disorders.

It can also occur for reasons that are not dangerous.

What matters is whether the sensation is persistent, unexplained, or accompanied by other symptoms.

If you repeatedly feel unable to completely empty your bowel, particularly if you also experience bleeding, mucus, pain, diarrhea, constipation, or unexplained weight loss, discuss it with a healthcare professional.

These Symptoms Do Not Automatically Mean Colon Cancer

One of the most important things to understand is that these symptoms are not specific to colorectal cancer.

The same symptoms can occur with many less serious conditions.

For example:

Hemorrhoids

Hemorrhoids can cause bright red rectal bleeding, itching, discomfort, or irritation.

Constipation

Constipation can cause abdominal discomfort, hard stools, straining, bloating, and a feeling of incomplete evacuation.

Irritable Bowel Syndrome