Mucus and blood in stool with abdominal pain: 6 Causes explained.

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Common causes of abdominal pain, with blood and mucus in the stool are:

  • Dysentery: the most common cause of acute abdominal pain with blood and mucus in stool.
  • Inflammatory bowel disease (Crohn’s and Ulcerative Colitis).
  • Proctitis (inflammation of the rectum).
  • Diverticulitis.
  • Colorectal cancer.
  • Intussusception.


1- Dysentery.


A dysentery is a severe form of intestinal infection. Dysentery is characterized by severe diarrhea, blood, and mucus in stool together with abdominal pain.

Dysentery is caused by a variety of organisms. The two most common organisms causing dysentery are

  • Entamoeba histolytica (Amoebic dysentery).
  • Shigella bacteria (Bacillary dysentery).

Symptoms and character:


  • Acute onset lasts for a short duration (usually, 3-7 days).
  • Abdominal pain.
  • sudden diarrhea.
  • In severe condition, only mucus and blood comes out without poop.
  • Urgency: sudden and intense desire to poop while scanty blood and mucus come out.
  • Frequency: several attacks of diarrhea, blood, or mucus.
  • Tenesmus: a sense of incomplete evacuation.
  • Fever that may exceed 100.4° F (38° C).
  • Signs of dehydration (if the condition is severe): such as extreme thirst, dry mouth, and dizziness.

The differences between amoebic dysentery and bacillary dysentery:


TypeAmoebic dysenteryBacillary Dysentery
1- CauseEntamoeba histolyticaShigella bacteria.
2- the severity of diarrheaAbout 6-8 motions/dayMore than 10 motions
3- SmellFoul-smellingNone
4- Color of blood in stoolDark redBright red
5- Stool formBlood & mucus mixed with stoolBlood and stool without a stool.
6- motion amountrelatively copiousscanty amounts.
7- Feverlittle fever in adultHigh grade.
8- TenesmusmoderateSevere.


What to do if you think you have Dysentery?


A dysentery is a severe form of gastrointestinal infection. This is more evident with bacillary dysentery due to severe symptoms.

Sometimes, having an attack of dysentery requires medical treatment to prevent complications. However, symptoms will go on their own within 3-7 days.


General treatment tips: 

  • Rest.
  • Drink plenty of fluids.
  • Eat bland foods such as bananas, rice, toast, and apple sauce (BRAT).
  • Over-the-counter antispasmodics and antidiarrheals such as Bismuth subsalicylate (Pepto-Bismol).
  • Wash your hands, stay away from close personal contact and sexual activity to avoid passing out the infection to others.
  • In severe cases, your doctor will prescribe antibiotics (Metronidazole for amoebic dysentery), and even intravenous fluids for severe cases. 


2- Inflammatory bowel diseases.


Inflammatory bowel disease is a term used to describe 2 diseases; ulcerative colitis and Crohn’s disease.

Both diseases are characterized by abdominal pain, blood, and mucus in stool. Undiagnosed inflammatory bowel diseases will lead to chronic abdominal pain and stool changes. 

Inflammatory bowel disease is characterized by prolonged inflammation and damage to the lining of the gut tract. The exact cause is still unknown, but it is thought to be an immune-mediated disease.

symptoms of IBD:

  • Persistent or recurrent diarrhea.
  • Abdominal pain.
  • Blood or blood and mucus coming out with or without a stool.
  • Weight loss.
  • Generalized fatigue.
  • Fever may occur.
  • Loss of appetite.

Suspect IBD if you have a prolonged history of abdominal pain, mucus, and blood in stool without obvious cause.

For doctors to diagnose IBS, they usually need to perform a colonoscopy. A colonoscopy will help visualize the lesion, and your endoscopist may take a biopsy to confirm the diagnosis. (ref)


Here are the main differences between Crohn’s and ulcerative colitis:


TypeCrohn’s DiseaseUlcerative Colitis
1- SiteAny part of the GI tract (from the mouth to the anus)The colon and rectum.
2- LesionsDeeper, it can involve all the layers of the GI wall.Usually superficial (only in the innermost layer)
3-Predominant symptomCrampy abdominal painBloody diarrhea.
4- ComplicationsFistulas, abscess, intestinal obstructionhemorrhagic toxic megacolon.
5- Risk of colon cancerSlight increaseMarked increase


Ulcerative colitis and Crohn’s disease are major diseases that require medical care and follow-up. Patients always receive strong anti-inflammatory medications such as corticosteroids. If you have a long history of recurrent abdominal pain, blood, and mucus in stool, consult your doctor.


3- Proctitis.


Proctitis is a term used to describe the inflammation of the rectum. Proctitis occurs due to a wide variety of causes. The presence of blood and mucus with stool, together with severe tenesmus and lower abdominal pain is suggestive of proctitis.


Common causes of proctitis include:


  • Dysentery (explained before).
  • Inflammatory bowel disease.
  • Sexually transmitted diseases of the rectum and anal canal.
  • Rectal ulcers.
  • Anal or rectal abscesses or fistulas.
  • Severe forms of food allergy or intolerance.
  • Ano-rectal cancers.
  • Radiation colitis and proctitis.
  • Diversion colitis and proctitis. 


Proctitis symptoms include:


  • A continuous feeling that you need to have a bowel movement (Tenesmus).
  • Rectal bleeding.
  • Passage of mucus, alone or with blood and stool.
  • abdominal pain (particularly in the lower left side of your abdomen).
  • Diarrhea.
  • Painful bowel movements.

Learn more.


4- Diverticulitis.


Diverticular disease is a condition that affects your colon as your get older. Diverticula are small pocket-like bulges in the lining of the colon.

Usually, the diverticula are asymptomatic. However, the diverticula can inflame and cause symptoms.

The inflamed diverticula are called “diverticulitis”. Diverticulitis can cause severe symptoms such as abdominal pain, blood, and mucus in stool.


Symptoms of diverticulitis:


  • Abdominal pain, usually in the lower-left side of your abdomen. The pain gets worse shortly after eating. 
  • When the inflammation starts, the pain becomes constant and more severe. 
  • Blood, mucus with stool.
  • Frank rectal bleeding can also occur.
  • Fever.
  • Nausea and lost appetite.


Contact your doctor as soon as possible if your suspect diverticulitis. A colonoscopy is needed to diagnose such a condition.

Learn more.


5- Colorectal cancer.


Colorectal cancer is a common disease nowadays.

The American Cancer Society estimates that 1 in 21 men and 1 in 23 women in the united states will develop colorectal cancer in the USA. (ref)

It is rare for colon cancer to present with abdominal pain. However, blood in stool is very common with colon cancer.

Colon cancer risk increases with age (especially after the age of 50). And that is why it is vital to undergo regular colonoscopy screening.

Symptoms of colorectal cancer:

1- Altered bowel movements (constipation or diarrhea): present in 75% of patients.

2- Dark or bright red blood in stool: present in 50% of colorectal cancer patients.

3- A sense of mass in the rectum (in 25%).

4- Anemia (iron deficiency) in 10%.

5- Isolated abdominal pain: is present in only 3.8% of cases (Another cause to have regular colonoscopy screening).

6- Other symptoms such as unexplained weight loss, fever, and anorexia. 


although the combination of blood, mucus, and abdominal pain are less common with colorectal cancer. But you should consider such a cause especially if you are older than 50.


Learn more: The differences between IBS and colon cancer symptoms.


6- Intussusception.


An intussusception is a serious form of intestinal obstruction where a part of your intestine slides into the adjacent part (called the telescoping action). 

This leads to obstruction of your intestine and cutting off blood supply to the affected part. 

Intussusception primarily affects children. It can also occur in adults but it is rare.


Symptoms include:

  • sudden onset of severe abdominal pain.
  • Stool mixed with blood and mucus.
  • Sometimes it has a characteristic shape called “currant jelly stool”.
  • a lump sensation in the abdomen.
  • Diarrhea. 
  • vomiting and severe nausea.