While people often associate mucus with illness or disease, it plays an important role in many of the body’s healthy functions. Still, it can be alarming when stools suddenly contain large amounts of mucus. Any change in stool’s consistency, color, or frequency is a sign of potential illness. Mucus in stools can indicate many issues that vary greatly in severity.

Underlying Causes

The large intestine’s mucous membrane enables easier bowel movements and defends against pathogens. Because of this membrane, all stools contain a slight amount of unnoticeable mucus. However, certain inflammatory processes can break down the mucosal layer and increase stool mucus levels. Other issues may increase mucus production or accumulation.

Bacterial and Parasitic Infections

Some of the most common causes of mucus in stools are bacterial infections from Salmonella, C. difficile, Campylobacter, or Shigella. These lead to food poisoning and similar issues that increase the amount of mucus in stools. Signs of a bacterial infection include diarrhea, cramping, nausea, fever, and vomiting. Parasitic infections, such as trichomoniasis and malaria, may also be responsible for mucus in stools.

Anal Fissures and Ulcers

Anal fissures are tears in the moist mucosa that lines the anus. They result from frequent diarrhea, firm stools, and other bowel issues. While painful, anal fissures are often minor and heal with time. Ulcers can have similar qualities to anal fissures and also lead to mucus in stools. Both may result from underlying conditions that affect the mucous membrane of the large intestine.

Bowel Obstructions

Impacted stools, hernias, tumors, ulcers, and the passing of a non-food item can obstruct the bowels. A bowel obstruction often causes simple issues like cramps, constipation, gas, vomiting, or bloating. However, mucus and fluid will begin to escape from the impacted stool, leading to noticeable mucus leakage and fecal incontinence. After the bowel obstruction clears, the next several bowel movements may have mucus-rich stools.

Serious Conditions

Conditions such as irritable bowel syndrome (IBS) and cancer can increase mucus production. Typically, mucus production is more common in people with diarrhea-predominant IBS than constipation-predominant IBS. Ulcerative colitis may lead to inflammation of the large intestine, causing it to develop ulcers that produce pus and mucus. These more serious issues usually cause bleeding that is noticeable in the stool itself or on toilet paper after wiping.

Diet and Simple Issues

Food allergies may contribute to mucus levels in stools, and also tend to cause bloating, diarrhea, rashes, and constipation. Even simple issues like diarrhea may lead to dehydration that causes excess mucus to accumulate and attach to stools. Allergies or food intolerances may also cause inflammation that affects mucus production. If mucus levels in stools only increase after eating a specific food, an allergy is probably responsible.

Diagnosis

Unusual mucus in stools has many causes, making diagnosis difficult. A doctor’s goal is to determine what underlying issue triggered the increase. Diagnosis begins with a physical exam and blood test. Other tests may include stool cultures, colonoscopies, endoscopies, imaging tests, and urinalysis. For simple issues, the doctor may be able to quickly make a diagnosis. More difficult problems may require several rounds of tests.

Treatment

The treatment for mucus in stools will vary depending on the underlying condition. For simple issues, minor lifestyle changes, such as increasing fluid intake or following a healthy diet, can resolve the symptom. Prescription medications may be necessary for conditions like IBS or ulcerative colitis. Anal fissures or similar problems may resolve on their own. Less commonly, chronic anal fissures may require surgical procedures.

Prevention

Mucus naturally exists in stools, so it is not possible nor advisable to prevent it entirely. However, maintaining a healthy diet, drinking plenty of fluids, and taking probiotic supplements can protect against infections and similar issues that may increase mucus levels. More serious conditions are not as simple to prevent, but regular screening can help catch them early in their progression.

Emergency Symptoms

If there is a significant increase of mucous in the stool, it is important to speak with a medical professional. Bleeding or changes in bowel habits are other signs to look out for. Bloody, mucus-rich stools that accompany abdominal cramping or similar symptoms indicate a serious condition.