Causes of Mucus in Diarrhea

Medically Reviewed by Poonam Sachdev on May 29, 2024
5 min read

Your intestines normally produce mucus to keep your colon moist. Mucus has the consistency of jelly.

A small amount of mucus in your poop is normal, but sometimes it could indicate a condition that needs treatment.

If the layer of mucus in your colon gets damaged, you'll see a lot more mucus in your stool. If you have diarrhea with mucus, inflammatory bowel disease or an infection could be to blame. It can be accompanied by blood and fevers.

Urge to poop but only mucus comes out

This is sometimes called "rectal spitting," and it's a sign of inflammation in your rectum. Inflammation can be caused by bacteria or chemicals. It also can be caused by inflammatory bowel disease (IBD). This could be a sign of a digestive disorder. But if you have rectal spitting, it also could be a sign of:

  • Hemorrhoids
  • A sexually transmitted infection
  • Food poisoning

Diarrhea with mucus in babies

A small amount of mucus in your baby's poop is normal. But if your baby has three or more watery or loose stools, doctors consider that diarrhea. Many things can cause babies to have diarrhea, with or without mucus. They include:

  • Viruses such as rotavirus
  • Bacteria such as salmonella
  • Giardia, an infection more common in group settings such as day care
  • Food poisoning, which is caused by infected food (can be related to travel)
  • Antibiotics
  • Cow milk allergy
  • Lactose intolerance
  • Food moving rapidly from stomach to anus (sometimes called "toddler's diarrhea")

In IBS, there's a breakdown between how your brain and gut talk to each other. When you have this condition, certain foods, stress, or changes in your hormones can make your colon spasm. This pushes food too quickly through your system and causes it to come out as watery or mucus-filled diarrhea.

Symptoms of IBS vary widely. Besides mucus-filled diarrhea, you could have:

  • Belly pain that doesn't go away or gets better after a bowel movement
  • Constipation, diarrhea, or both
  • Gas
  • Bloating
  • Swollen belly
  • Wanting to poop but feeling that you can't

As changing what you eat helps many people with IBS, you may want to speak to a dietitian. Counseling and acupuncture can offer relief, and your doctor can prescribe medicines to ease your everyday symptoms.

Bacteria (and rarely viruses) that cause food poisoning and invade the colon lining can lead to mucus in the stool. This also causes blood in stool and/or fever. "Stomach flu" affects the upper gastrointestinal tract and doesn't tend to cause mucus.

If you have mucus in your diarrhea because of an infection, you may also have symptoms such as:

You need to treat your digestive symptoms gently when you're sick. Stay away from caffeine, alcohol, and spicy or fatty foods. Sip water so you don't get dehydrated.

It's also wise to check in with your doctor. Though many infections that affect your gut go away on their own, sometimes you need antibiotics or medicine that can stop your diarrhea. Always see your doctor if you notice blood in your stool.

This inflammatory bowel disease (IBD) causes long-term inflammation and ulcers in your digestive tract. That's a tube that extends from your mouth to your anus and includes the small intestine and colon.

Your small intestine and colon are likely to become inflamed when you have Crohn's disease. You may have diarrhea with mucus in it.

You might also have symptoms such as:

  • Blood in your stool
  • An urgent need to poop
  • A feeling that you can't get all your stool out
  • Stomach cramps
  • Constipation
  • Weight loss

If you think you have Crohn's, see your doctor. Though there's no way to get rid of it for good, medications and changes to what you eat can ease your symptoms and stop your condition from getting worse. Some people may need surgery.

Another type of inflammatory bowel disease, ulcerative colitis causes sores to form inside your colon and rectum. You could start to have mucus-filled diarrhea right before other symptoms start to flare.

Other common signs of UC include:

  • Cramps
  • Frequent need to poop
  • Blood in your stool
  • Belly soreness or pain
  • Fatigue

See your doctor if you have these symptoms. There's no cure for UC, but you can learn about treatments that manage your symptoms.

It's still unclear what causes cancer to grow in your colon or rectum, the tube that sends your stools to your anus. Severe UC or Crohn's can raise your risk for this cancer. Also, if you eat lots of high-fat, low-fiber foods or drink a lot of alcohol, you're more likely to get colorectal cancer.

Besides mucus in your diarrhea, common symptoms are:

  • Constipation or pencil-thin stools
  • Cramps
  • Nausea
  • Gas
  • Bloating
  • Feeling like you can't get all your poop out
  • Bright or dark red blood in your stool
  • Low energy
  • Weight loss

If you have any of these signs, see your doctor right away. Surgery, chemotherapy, and radiation are options to treat colon cancer.

Mucus in diarrhea, either in adults or babies, can be a sign of many illnesses. Your body produces mucus naturally in your colon to help keep your digestive system lubricated. However, diarrhea with mucus can be a sign of inflammation in your digestive system. You might have an infection. Other possibilities include irritable bowel syndrome (IBS), Crohn's disease, ulcerative colitis (UC), and colorectal cancer.

Can IBS cause mucus in diarrhea?

Yes, mucus in your poop can be a sign of irritable bowel syndrome.

Why is there mucus in my stool when I have diarrhea?

Mucus in diarrhea is a sign that your digestive system is dealing with some kind of inflammation. This could be caused by an infection, or it could indicate diseases such as Crohn's, ulcerative colitis, irritable bowel syndrome, or colorectal cancer.

Does ulcerative colitis cause mucus in stool?

Ulcerative colitis can cause mucus in your poop. You also might have bloody diarrhea.