Why Is There Mucus in My Stool? Causes and Symptoms Explained

Mucus in stool can be caused by infection, IBS, or inflammatory bowel disease. See a doctor if it is frequent or comes with blood or pain.

Normal

A small amount of clear or white mucus is normal.

Possible causes

• Infection.
• IBS.
• Crohn’s disease or ulcerative colitis.
• Anal fissures.
• Food intolerance.
• Rarely, colorectal cancer.

When to worry

Large amounts, blood, pain or lasting change.

See a doctor

If it is frequent or comes with blood, weight loss or fever.

What mucus does

The intestines produce mucus to lubricate the colon wall and help stool pass. Small amounts of clear or white mucus in the stool can be normal and often go unnoticed.

Causes of more noticeable mucus

• Dietary changes or mild dehydration.
• Constipation.
• Irritable bowel syndrome (IBS).
• Gastroenteritis (stomach infection).
• Food intolerances such as lactose.
• Inflammatory bowel disease (ulcerative colitis, Crohn’s disease), which can cause mucus with blood.
• Anal fissures, hemorrhoids or fistulas.
• Bowel obstruction.
• Bacterial infections such as Salmonella, Shigella or Campylobacter.
• Colorectal polyps or cancer, less commonly.
• Celiac disease.

Infants

Mucus in a baby’s stool may come from teething, drooling, cold or a mild infection, and is often harmless. Persistent mucus with blood or fever needs a pediatrician’s visit.

Characteristics that matter

Yellow, green or red mucus, large amounts, frequent mucus, or mucus with blood, pus, pain or weight loss.

What to do

• Drink water and eat fiber.
• Track symptoms and foods.
• Avoid known triggers.
• Probiotics may help IBS in some people.

Tests

Stool tests, blood tests, colonoscopy or imaging.

See a doctor if

Mucus lasts more than a week, increases, or comes with blood, abdominal pain, diarrhea, fever, weight loss or a change in bowel habits. Adults over 45 should have routine colon cancer screening.

Emergency

Severe abdominal pain with vomiting, bloating and inability to pass gas needs urgent care.

Mucus function and typical amounts

The colon lining produces mucus that lubricates stool and protects the intestinal wall, so small, clear amounts mixed with stool are normal and often unnoticed. More visible white or yellow mucus may appear with irritable bowel syndrome, infections, food intolerances, anal fissures, hemorrhoids, and inflammatory bowel diseases such as ulcerative colitis and Crohn disease. Mucus with blood, pain, fever or diarrhea is more concerning. Rarely, colorectal cancer or polyps can produce mucus.

What to do

Doctors may order stool tests, blood tests, imaging or colonoscopy. Treat the cause: increase fiber, avoid trigger foods and manage stress for IBS. See a doctor if mucus is persistent for more than two weeks, increases, or comes with blood, weight loss, abdominal pain or changes in bowel habits. In infants, small amounts of mucus with teething or a cold are common, but blood or fever needs a pediatrician. Go to the emergency room for severe pain, high fever or heavy bleeding.

Based on data from the Crohn’s and Colitis Foundation and the Mayo Clinic