Difference Between Diarrhea and Dysentery


Main Difference

The main difference between diarrhea and dysentery is that diarrhea is the disease of small intestine whereas dysentery is the disease of the colon.

Diarrhea vs. Dysentery

Diarrhea is characterized as abnormally loose or watery stools with inflammation of small intestine whereas dysentery is described by mucus or blood in stool with abdominal pain and cramps because of inflammation of the colon. The causes of diarrhea are Bacteria (Salmonella, Campylobacter, Shigella and Escherichia coli), virus and parasitic organisms. Besides microorganisms, some diseases and drugs are also responsible for diarrhea; On the other hand, dysentery is caused by bacteria (Shigellosis, Amoeba) chemical irritation, virus, and unsanitary conditions. In the case of diarrhea, targeted cells are intestinal lumen and upper epithelial cells while in the case of dysentery, targeted cells are upper epithelial cells. Untreated diarrheas can result in two complications; dehydration and malabsorption whereas untreated dysentery can also result in various complications; dehydration, liver abscess, postinfectious arthritis, and hemolytic uremic syndrome.


Comparison Chart

Diarrhea is a disease of the small intestine due to E.Coli bacteria which results in a watery stool, accompanied by abdominal pain, fever or crampsDysentery is the disease of the colon due to E.Coli, Shigella, Salmonella and results in mucoid and bloody stool which can also result in abdominal pain, cramp, vomiting, high fever, and weakness
Signs and Symptoms
Watery stool with no blood and mucusMucoid stool with or without blood
Causative Agents
E.ColiE.Coli, Shigella, Salmonella
Affected Area
Small intestineColon
Targeted cells
Intestinal lumen and upper epithelial cellsUpper epithelial cells
Cell death
No cell deathCell death may occur
Risk Factors
Age, children are at high risk, environment, medications, comorbiditiesPoor hygienic conditions
ORS, Intravenous liquid, medicines, probioticsORS, Intravenous liquid, medicines
Home Remedies
· Drink water frequently
· Do not use milk
· Avoid a fat-rich diet
· Drink water frequently
· Do not use milk
· Avoid a fat-rich diet

What is Diarrhea?

Diarrhea is the disease of the small intestine. Diarrhea is of three types osmotic diarrhea, secretory diarrhea, and inflammatory and infectious diarrhea. Osmotic diarrhea occurs because of ingestion of poorly absorbed substrate and malabsorption. Absorption of water in the intestine is dependent on the adequate intake of solutes. If excessive solutes are retained in the intestine, then the liquid will not be absorbed, and osmotic diarrhea will occur. Significant volumes of water are generally secreted into the small intestine, but a large amount of water is efficiently absorbed before reaching the large intestine. Secretary diarrhea occurs when the secretion of water into the intestine exceeds absorption. In infectious diarrhea, epithelium of the digestive tract breaks down because of attacking pathogens. Disruption of the epithelium results in an exudation of serum and blood into the lumen and insufficient absorption of water occurs and diarrhea results.


Doctors diagnose diarrhea by symptoms, current medications, medical history, and other associated medical diseases. But if a person complaints chronic or persistent diarrhea then the doctor can refer for different tests, full blood count, liver function test, tests for malabsorption, Erythrocyte sedimentation rate (ESR) and checks for antibodies.


For all types of diarrhea, rehydration is a vital treatment. Different kinds of Oral Rehydration Solutions (ORS) are available. Loperamide and Bismuth subsalicylate are antidiarrheal medicines. Antibiotics are also used for the treatment of diarrhea if the cause is bacteria. Besides all these, probiotics and modifications in diet can also help treat diarrhea.

What is Dysentery?

Dysentery is the disease of the colon. There are mainly two types of dysentery; Bacillary dysentery and Amoebic dysentery. Bacillary dysentery is also known as shigellosis and caused by a group of bacteria shigella species. Amoebic dysentery is also known as amoebiasis and created by a protozoan, Entamoeba Histolytica. Besides these, there are some other bacteria causing dysentery. Dysentery causes about 120 million and 165 million cases of infection, of which 1 million are dangerous. 60% of fatal cases are of children under five years old in developing countries.


The doctor will diagnose dysentery by signs and symptoms and physical examination. A sample of stool may be taken, and if the condition is severe, then diagnostic imaging will be recommended.


Laboratory tests will determine the type of dysentery either mild bacillary dysentery or amebic dysentery. Mild bacillary dysentery will resolve without any significant treatment, but if not alleviate then antibiotic drugs are available. For amebic dysentery, Flagyl and metronidazole are available.

Key Differences

  1. Diarrhea affects small intestine whereas dysentery affects the colon.
  2. In diarrhea, the patient may or may not accompany with abdominal cramps and pain whereas, in dysentery, the patient is usually accompanied by abdominal cramps and pain.
  3. Fever is less common in diarrhea where it is more common in dysentery.
  4. In diarrhea, infection usually attacks intestinal lumen and upper epithelial cells whereas in dysentery, infection attacks not only upper epithelial cells but also causes ulceration.
  5. In diarrhea, cell death does not occur and infection results because of toxins released by infecting agent whereas in dysentery cell death occurs because of attacks by the causative agent.
  6. In diarrhea, antimicrobial agents are not needed for treatment; it can be cure by ORS, whereas dysentery needs antibiotics for eradication.
  7. Diarrhea does not cause any severe effect whereas dysentery causes complications if left untreated.


From the above discussion, it is clear that diarrhea and dysentery are the clinical conditions of the gastrointestinal tract. Diarrhea is the inflammation of the small intestine while dysentery is the inflammation of the colon.

Janet White

Janet White is a writer and blogger for Difference Wiki since 2015. She has a master's degree in science and medical journalism from Boston University. Apart from work, she enjoys exercising, reading, and spending time with her friends and family. Connect with her on Twitter @Janet__White