Pooping Mucus Only: 12 Causes Explained (Dr. Farahat).

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What you need to Know about pooping mucus only:


Usually, pooping mucus only is a result of severe inflammation or infection of the last part of the colon or the anal canal. Common causes include is dysentery, STDs of the anorectal canal, inflammatory bowel diseases, anorectal fissures, or inflamed hemorrhoids.

Common causes of pooping mucus only include:

  • Bacillary dysentery: is more likely to cause mucus-only poops than other causes of dysentery
  • Sexually-transmitted diseases of the Anorectal canal are also a common cause of mucus in stool.
  • Inflammatory bowel disease: Crohn’s and ulcerative colitis.
  • Inflammed anorectal fissure or hemorrhoids.
  • Irritable bowel syndrome.
  • Rectal ulcers.
  • anorectal abscess/fistulas.
  • Antibiotic-associated colitis.
  • Food intolerances.
  • Anorectal cancers.
  • Radiation colitis, proctitis.
  • Diversion colitis.
pooping mucus only

1. Bacillary dysentery.


Dysentery is the passage of blood, mucus, or both with stool. Dysentery is usually caused by infections of your colon (large intestine).

If the colon inflammation is severe or involves the rectum, it can lead to mucus-only poop (mucus discharge).

Two main organisms can cause dysentery:

  • Shigella bacteria: causes bacillary dysentery.
  • Entamoeba Histolytica protozoan: causes amoebic dysentery.

Dysentery is the most common cause of pooping mucus, but Bacillary dysentery is more severe and more likely to cause mucus-only poop. This is because Shigella commonly causes proctitis (rectal inflammation).

You can get infected by shigella via contaminated food (food poisoning) or touching contaminated surfaces. Shigella is highly contagious even and may cause outbreaks of dysentery, especially in children.

Symptoms suggest bacillary dysentery.

  • The onset is acute, if you have recurrent mucus poop, dysentery is unlikely.
  • Intense abdominal pain, especially in the lower abdomen.
  • Diarrhea is associated with mucus and blood.
  • In severe cases, mucus only stools. Mucus and blood can come out without feces.
  • Tenesmus: intense urgency to poop, but only mucus or a small amount of poop comes out.
  • Fever: usually high grade.
  • nausea or vomiting (rarely present with bacillary dysentery).

Bacillary dysentery symptoms can range from mild diarrhea to intense dysentery, blood or mucous stools, and high-grade fever.

Mild symptoms are usually self-limiting, but severe forms of the disease (such as mucus-only poop) require you to seek medical help.

2. Amoebic dysentery.


Entamoeba Histolytica is a common protozoan that can cause dysentery with blood and mucus in stool.

Amoebic dysentery is usually milder than bacillary dysentery. It is less likely to cause mucus only poop, but it happens with severe forms of the disease.

Symptoms of amoebic dysentery are similar to bacilliary dysentery, the main differences are:

  • The onset is more gradual (usually over one to three weeks), and the severity is less than bacillary dysentery.
  • can range from mild diarrhea to severe dysentery with mucus and blood in the stool.
  • abdominal pain and fever are milder.
  • Tenesmus is moderate.
  • The stool is usually more formed and bulky, blood and mucus are usually mixed with feces (with bacillary dysentery, blood and mucus come out without feces).
  • In severe cases, Entamoeba organisms can invade the wall of the colon and cause intestinal perforation and cause fulminant inflammation of the colon.

The video below explains dysentery simply:

3. Other infections and food poisoning (foodborne illnesses).


Some other infections (especially bacteria) can infect your colon and rectal canal and cause mucus-only poop.

Some other causes of dysentery and mucus only poop (ref):

  • Salmonella (typhoid fever).
  • E. coli (Shiga toxin-producing, Entero-invasive E. coli).
  • Clostridium Difficile.
  • Cytomegalovirus colitis.
  • And other less common organisms.

The above organisms can cause dysentery with mucus and blood in the stool. symptoms may vary from mild to severe and persistent illness.

The acute onset and presence of intense abdominal pain and fever are suggestive of infectious diarrhea and dysentery.

4. Sexually transmitted diseases (STDs) of the Anorectal canal.


Sexual activities involving the anorectal canal can lead to infections, inflammation, and ulcers. Not all STDs of the anorectal canal lead to mucus in stool.

Possible organisms that can cause tenesmus and mucus poop:

  • Anorectal Gonorrhea.
  • Chlamydia causes severe tenesmus, rectal ulcers, mucus, and blood in the stool. it is possible to have mucus-only poop with chlamydia infection of the anorectum.
  • Syphilis causes painful ulcers and anorectal pain and discharge (which can be mucus).
  • Sexually transmitted campylobacter Jejuni: causes ulceration of the rectal mucosa, diarrhea (which can be bloody and mucous, cramps, bloating, mucus in stool.

When to suspect:

  • Recent anorectal sexual activities with an infected or carrier partner.
  • Your partner doesn’t need to have symptoms.
  • The most commonly reported sexually transmitted disease in the USA is Chlamydia. it can cause rectal ulcers or access. this presents with severe anorectal pain, mucus-only poop, or pus discharge.
  • Fever may also present.

5. Anal Fissure


An anal fissure is a breakdown in the lining of the anal canal. It leads to anorectal pain and severe irritation which can lead to mucus or pus discharge instead of poop.

Fissures commonly occur due to:


  • Severe anorectal pain increases while your poop is the main symptom. Almost, there is no fissure without sharp pain.
  • History of the causes such as severe constipation or local trauma to the anus.
  • With chronic fissures, you may feel a skin tag at the opening of your anal canal.

What to expect:

  • Your doctor will confirm the fissure by performing a local exam of the anorectal canal.
  • Most acute fissures will resolve within a few weeks, but they may turn chronic.
  • Treatment can include oral medications, local creams, or even surgery in severe cases.
  • The most important step is to prevent the cause such as treating constipation and eating a high-fiber diet.

6. Inflamed Hemorrhoids.


Hemorrhoids are dilated inflamed veins in the wall of the anorectal canal. Inflamed hemorrhoids can irritate the canal and secrete mucus.

Mucus from the inflamed hemorrhoids can come out without stool. It is associated with the urge to poop even after having a bowel movement (ref).

A bulge or a skin tag may be felt at the opening of the anus. Whether you are diagnosed with hemorrhoids before or not, you have to see your doctor if you’re pooping only mucus with the hemorrhoids.

7. Inflammatory Bowel Diseases (Crohn’s & Ulcerative Colitis).


Inflammatory Bowel Disease is a term to describe two conditions (Crohn’s disease and ulcerative colitis). A disease that is caused by chronic inflammation and ulcers in the digestive tract.

The cause of IBD is unknown, but it is thought to be a result of a defective immune system (an autoimmune disease) (ref).

Ulcerative colitis affects only the large intestine (usually the last part including the descending colon, sigmoid colon, and the rectum). Crohn’s disease affects any part of your digestive tract from the mouth to the anus.

Chronic inflammations and ulcers (especially in the last part of the colon and the rectum) can lead to recurrent diarrhea, stool urgency, blood, or mucus in stool. bloody and mucous discharge is more common with Ulcerative colitis (ref).

Symptoms suggesting IBD:

  • Persistent diarrhea.
  • Abdominal pain.
  • Rectal bleeding/Bloody stool.
  • The severe urge to poop but only mucus or blood comes out (tenesmus).
  • Weight loss.
  • Fatigue.
  • Mucus in the stool.
  • Fever may occur.

Mucus-only poop can be a result of the affection of your anorectal canal with either Crohn’s or ulcerative colitis. Either inflammation or ulcers lead to increased mucus in the anorectal canal which can come out without poop.

The diagnosis of Inflammatory bowel disease usually requires colonoscopy. It is treated with medications that decrease inflammation and suppress immunity (such as corticosteroids) (ref).

8. Irritable bowel syndrome (especially the diarrhea-predominant form).


Irritable Bowel Syndrome is very common, up to 15% of all people suffer from manifestations of IBS (ref).

IBS is a common cause of mucus in stool. Although it is possible to poop only mucus with IBS, usually mucus comes with the stools.

IBS is an underdiagnosed condition, it is estimated that up to 70% of people with IBS criteria don’t seek a diagnosis.

symptoms suggesting IBS (ref):

  • Recurrent abdominal pain at least one day per week for the last 3 months.
  • The onset of pain is associated with stool frequency (diarrhea or constipation).
  • The abdominal pain is relieved (or increased) after defecation.
  • Change in stool form (loose or hard stools).
  • Mucus in stool, or rarely, mucus only stool.
  • Absence of other causes of the above symptoms.

Read this in-depth article about how is IBS diagnosed.

If you have symptoms consistent with IBS, seek medical advice. And remember, Mucus-only stools are rare with IBS.


9. Anorectal abscess or perianal fistula.


The abscess is an infected sac of tissue in the wall of the anorectal canal filled with pus.

The fistula is a small channel that connects an infected anal gland (in the tissue near the anus) to an opening on the skin.

Both conditions can lead to the discharge of blood, pus, or mucus from with or without a stool. the conditions usually present with:

  • Swelling, severe pain, or tenderness of the perianal tissue.
  • Rectal discharge (blood, pus, or mucus only poop).
  • Constipation (as a result of fear of painful bowel movements).
  • Fever and fatigue may occur.
  • You may have an opening discharging pus or blood in the perianal area (Perianal Fistula).

10. Rectal ulcers.


Rectal ulcers are painful sores in the wall of your rectal canal. It can occur as a result of a variety of causes or due to a condition called solitary rectal ulcer syndrome (SRUS).

Common causes of rectal ulcers:

  • Inflammatory bowel diseases (Crohn’s and Ulcerative colitis).
  • Severe constipation.
  • Radiotherapy of the rectal canal
  • Ulcerated rectal tumor.
  • Solitary Rectal Ulcer Syndrome (SRUS): is a very rare disease.

Symptoms of rectal ulcers:

  • Blood or mucus discharge from the anus.
  • Rectal Pain.
  • Painful bowel movement.
  • Tenesmus: urge to poop but nothing comes out or only mucus or blood poop.

11. Antibiotic use.


Overuse of some antibiotics may cause an inflammation of the colon. Antibiotics can kill the beneficial micro-organisms inside your colon and small intestine.

As a result, you may acquire infection with harmful bacteria that cause severe inflammation of the colon and the rectal canal.

For example, Clostridium Difficile infection of the colon after antibiotic use. This usually occurs in people with a weakened immune system, using a medicine that reduces stomach acid, or having previous digestive system surgery.

Most antibiotics can cause such conditions, but strong antibiotics with a broad antibacterial spectrum such as penicillins, Cefotraxone, or ciprofloxacin. Also, using more than one antibiotic at the same time will raise the risk.

A severe condition with the destruction of the colon lining due to inflammation is called “pseudomembranous colitis” which may result from faulty use of antibiotics (ref).

This condition usually presents with intense diarrhea, blood, mucus in bowel movements, fever, and severe abdominal pain.

Contact your doctor if you experienced mucus-only poop after taking an antibiotic.

12. Food Intolerance.

Many foods can induce inflammation of the colon and rectal lining as a result of the sensitivity of your body to these diets.

severe inflammation of the lining will usually result in diarrhea, mucus in stool, or mucus-only stools in severe cases.

Common examples of food intolerance.

  • Lactose intolerance (milk and other dairy products).
  • Fructose intolerance.
  • FODMAP intolerance (as in people with IBS).
  • Gluten intolerance (present in wheat and barley): results in severe diarrhea and malabsorption, severe disease is called “celiac disease”. Also, some people may have Non-celiac gluten sensitivity (milder form).

Read more about food intolerance here.

RELATED: Flatulence and Mucus Discharge: 7 Causes Explained.


13. Less Common.


A- Colorectal Cancer.

a mass in the last part of the colon or the rectal canal may cause inflammation or ulceration. This can present with tenesmus, blood in the stool, or mucus discharge. Risk factors include being older than 40, having a family history of colorectal cancer, or weight loss.

colorectal cancer is one of the most common tumors. but its incidence as a cause of mucus-only stools remains low compared to the causes mentioned above.

Always consult your doctor if you have risk factors. learn more here

B- Anal cancer.

Anal cancer is a growth in the last part of the digestive tract. it usually presents with pain in the area of the anus, and a sense of mass inside the anus.

  • A sense of incomplete evacuation of stool.
  • Bleeding per anus.
  • perianal itching.
  • Mucus in the stool.

Learn more HERE.

C- Intestinal Obstruction.

a bowel obstruction can be caused by a variety of conditions such as:

  • Impacted hard stools.
  • scar tissues.
  • hernia
  • Tumors of the gut.
  • Swallowing of non-food items.
  • Twisting of the intestine.

Bowel obstruction presents with:

  • absolute constipation, No stool at all, only mucus poop can occur.
  • Abdominal distension and bloating.
  • severe abdominal pain.
  • Vomiting usually occurs, it can be persistent.

if you have absolute constipation, vomiting, severe abdominal distension, and mucus-only poops you have to seek medical help. The condition may require surgery to resolve.

Learn more at the Mayo clinic.


D- Radiation Therapy.

Radiation therapy for abdominal and pelvic tumors can result in severe inflammation of the anorectal canal. This can lead to mucus or blood in the stool. Consult your doctor if you experience mucus-only poop after radiotherapy.

E- Diversion Colitis.

Ostomy operations such as ileostomy or colostomy may lead to inflammation of the colon.

with ostomy operations, the stool leaves the body, not through the rectal canal, but through an artificial opening in your abdomen connected to a bag.

This leaves the rest of the colon and the anorectal canal empty from the stool. It is common to pass mucus-only poop in patients with ostomy operations. either due to inflammation of the colon (diversion colitis) or due to mucus build-up inside the non-functioning colon.

learn more here.

F- Eosinophilic Proctititis / Allergic colitis.

Another cause of mucus-only poop is the allergic inflammation of the colon or the rectal canal.

A condition called Eosinophilic proctocolitis is usually caused by a milk or soy protein allergy. usually more common in children.

Inflammed mucosa of the colon and the rectal canal leads to diarrhea, and mucus in stool.

This condition cal also presents later in the adolescent age (not restricted to early childhood). If the mucus only poop is associated with milk ingestion, seek medical help to diagnose the condition.

Learn more about this condition

When to see a doctor for mucus only poop.

Mild acute attacks of mucus-only poop are usually due to dysentery. a single day with diarrhea and mucus can be self-limiting especially if you are not feverish or dehydrated.

See a doctor if:

  • severe attacks of mucus in stool, with an urgency that lasts for more than one day.
  • Fever.
  • Intense abdominal pain.
  • Recurrent vomiting.
  • Prolonged mucus in poop for more than one month without explained cause.
  • weight loss.
  • Blood in stool.
  • Signs of dehydration such as dizziness, extreme thirst, shortness of breath, rapid heartbeats, or confusion.