Diarrhea is a familiar phenomenon defined as unusually frequent or unusually soft or liquid bowel movements. It is the opposite of constipation. The word diarrhea with its odd spelling is a near steal from the Greek diarrhoia meaning "a flowing through."
Diarrhea can be acute, that is, sudden in onset and short-lived, or it may be prolonged. Most acute episodes of diarrhea are due to viral infections and last three to five days. Prolonged diarrhea -- lasting more than four to six weeks -- usually is due to an underlying gastrointestinal disease, the most common of which are diseases that cause inflammation and malabsorption of food. Intermittent diarrhea, sometimes alternating with constipation, is part of a syndrome of functional bowel disease called irritable bowel syndrome (IBS). In most cases, treatment of diarrhea includes drinking plenty of fluids to prevent dehydration and over-the-counter remedies to decrease and solidify bowel movements. Evaluation by a physician generally is needed if diarrhea is severe, results in dehydration, persists for more than a couple of weeks (chronic diarrhea), or if there is a high fever or blood in the stools.
Other causes of persisting diarrhea include food-handler's diarrhea (Campylobacter infection and others), parasite infection (amebiosis, etc.), cholera, cryptosporidiosis, food poisoning, giardiasis, Norwalk virus, rotavirus, salmonellosis, shigellosis, traveler's diarrhea, and inflammatory bowel disease (Crohn's disease and ulcerative colitis), and medication toxicity.
Diarrhea and loose stools can be associated with
- pus or blood in the stool,
- watery stool,
- abdominal bloating,
- abdominal cramps,
- urgency of bowel movements, and
- belly pain.
Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.
Pictures, Images, Illustrations & Quizzes
Crohn's Disease Causes, Symptoms, Diet
What is Crohn's disease? Get more information on this digestive disorder and how Crohn's can affect your diet. Learn more about...
IBS - Irritable Bowel Syndrome: Symptoms, Diet, Treatment
What is irritable bowel syndrome (IBS)? Learn about symptoms, causes, and foods that trigger IBS. Get lifestyle tips for managing...
Irritable Bowel Syndrome (IBS) Quiz: Test Your Medical IQ
What are symptoms of irritable bowel syndrome (IBS)? Take this quiz and get quick facts on causes and treatment options for this...
Worst Foods for Digestion
Discover which foods to avoid in order to prevent diarrhea and digestive problems. Find out which foods can trigger diarrhea and...
Causes of Diarrhea
Addison disease is a hormonal (endocrine) disorder involving destruction of the adrenal glands (small glands adjacent to the...
Adenovirus infections are common and often have no symptoms. Adenoviruses cause illnesses like bladder infections, diarrhea,...
Adenovirus 14 (Killer Cold Virus)
Adenovirus infection, particularly Ad14, or the "killer cold virus" has been on the increase in the past two years. Symptoms...
Agoraphobia is a fear of being outside or of being in a situation from which escape would be impossible. Symptoms include...
Amebiasis (Entamoeba histolytica Infection)
Amebiasis is an infection caused by an amoeba. Signs and symptoms include bloody stools, abdominal pain, weight loss, fever, and...
Amyloidosis is a group of diseases resulting from abnormal deposition of certain proteins (amyloids) in various bodily areas. The...
Anal cancer, cancer located at the end of the large intestine, has symptoms that include anal or rectal bleeding, anal pain or...
Anthrax is a deadly infectious disease that may be transmitted to humans by infected animals or by biological warfare. There are...
Arsenic comes in two forms, inorganic and organic. Organic arsenic poisoning is usually not poisonous to humans; however,...
Bird Flu (Avian Influenza, Avian Flu)
Bird flu (avian flu, avian influenza) infection in humans may result from contact with infected poultry. There is a vaccine to...
Bocavirus infection is usually only found in those with lower respiratory infections or diarrhea. Symptoms include cyanosis,...
Celiac disease is a condition in which a person has inflammation of the small intestinal mucosa when exposed to gluten in the...
Chagas Disease (American Trypanosomiasis or Kissing Bug Disease)
Chagas disease is an infection caused by the T. cruzi parasite. Symptoms of Chagas disease include rash, swollen lymph nodes,...
Cholera is an infectious disease characterized by intense vomiting and profuse watery diarrhea and that rapidly lease to...
Chronic Fatigue Syndrome (CFS or SEID)
Chronic fatigue syndrome (CFS) or systemic exertion intolerance disease (SEID) is a debilitating and complex disorder...
Cold vs. Flu
Though the common cold and flu share many signs and symptoms, they are caused by different viruses. Signs and symptoms include...
Cold, Flu, Allergy Treatments
Before treating a cold, the flu, or allergies with over-the-counter (OTC) medications, it's important to know what's causing the...
Colitis (Symptoms, Types, and Treatments)
Colitis refers to inflammation of the inner lining of the colon. Symptoms of the inflammation of the colon lining include...
Colon cancer is a malignancy that arises from the inner lining of the colon. Most, if not all, of these cancers develop from...
Crohn's Disease (Symptoms, Causes, Diet, Treatment, Life Expectancy)
Crohn's disease is a chronic inflammatory disease, primarily involving the small and large intestine, but which can affect...
Cryptosporidiosis is an intestinal disease caused by the Cryptosporidium parasite. Symptoms include watery diarrhea, stomach...
Cyclospora Infection (Cyclosporiasis)
Cyclospora cayetanensis is a parasite that causes infection when humans ingest food contaminated with feces from an infected...
Cytomegalovirus (CMV) is a virus that is spread from person to person via spit, semen, vaginal secretions, urine, blood, sexual...
Dehydration is the excessive loss of body water. There are a number of causes of dehydration including heat exposure, prolonged...
Diabetes (Type 1 and Type 2)
Diabetes is a chronic condition characterized by high levels of sugar (glucose) in the blood. The two types of diabetes are...
Diverticulitis (Diverticulosis, Diverticular Disease)
Most people with diverticulosis have few if any symptoms at all. When people do experience signs and symptoms of diverticulosis...
E. coli (0157:H7) (Symptoms, Treatment, Prevention)
There are many types of E. coli (Escherichia coli). E. coli can cause urinary tract and bladder infections, or lead to sepsis. E...
Ebola (Ebola Virus Disease or Ebola Hemorrhagic Fever)
Ebola hemorrhagic fever (HF) is an often-fatal disease that causes fever, headache, vomiting, diarrhea, sore throat, stomach...
Exocrine Pancreatic Insufficiency (EPI)
Exocrine pancreatic insufficiency or EPI is a condition in which a person's pancreas can't produce or secrete certain enzymes...
The most common food allergies are to eggs, nuts, milk, peanuts, fish, shellfish, strawberries and tomatoes. Symptoms and signs...
Food Poisoning (Symptoms, Remedies, Treatment, Cure)
Food poisoning is common, but can also be life threatening. The symptoms for food poisoning are fever, abdominal pain, headache,...
Giardiasis (Giardia lamblia) is a parasite responsible for a common form of infectious diarrhea. The parasite lives in two...
Graft Versus Host Disease (GVHD)
Graft versus host disease (GVHD) is a condition that happens when immune cells from transplanted donor tissue attack the...
Graves' Disease (Symptoms, Causes, Diet, Treatment Options)
Graves' disease is an autoimmune disease that affects the thyroid. Some of the symptoms of Graves' disease include hand tremors,...
Hantavirus pulmonary syndrome (HPS) is a disease transmitted by rodents. Symptoms include fever and muscle pain. HPS can be...
HIV vs. AIDS
Human immunodeficiency virus causes HIV infection. Acquired immunodeficiency syndrome (AIDS) is a condition that results after...
Human Immunodeficiency Virus (HIV)
The human immunodeficiency virus (HIV) causes HIV infection and the acquired immunodeficiency syndrome (AIDS). Symptoms and signs...
Hunter Syndrome (Mucopolysaccharidosis II, MPS II)
Hunter syndrome (mucopolysaccharidosis II, MPS II) is an inherited or genetic disease. Signs and symptoms of Hunter syndrome...
Inflammatory Bowel Disease (Intestinal Problems of IBD)
The inflammatory bowel diseases (IBD) are Crohn's disease (CD) and ulcerative colitis (UC). The intestinal complications of...
Irritable Bowel Syndrome (IBS)
Irritable bowel syndrome (IBS) is a GI (gastrointestinal) disorder with signs and symptoms that include abdominal pain, bloating,...
Is Cholera Contagious?
Cholera is an infectious disease caused by the bacteria Vibrio cholerae. It's typically transmitted via infected fecal matter....
Is Malaria Contagious?
Malaria is transmitted via the bite of an infected mosquito. The incubation period for malaria depends upon the species of...
Is Pneumonia Contagious?
Pneumonia is inflammation of the lung usually caused by bacterial or viral infection (rarely, also by fungi) that causes the air...
Is Salmonella Contagious?
Salmonella is a bacteria that can cause a variety of diseases. Salmonella can be transmitted via direct and indirect contact....
Is the Ebola Virus Contagious?
Ebola hemorrhagic fever is a highly contagious disease that is transmitted through direct contact. Ebola's incubation period...
Jet lag (desynchonosis) is a temporary disorder that results from travel across time zones. Symptoms include anxiety,...
Lactose intolerance is a common problem where a person's digestive system cannot digest lactose. Signs and symptoms include:...
Lassa fever is a viral hemorrhagic fever that causes flu-like symptoms. Ribavirin is the standard treatment for Lassa fever....
Legionellosis is an infection caused by the Legionella pneumophila bacterium. There are two forms of legionellosis: Pontiac fever...
Listeria is a type of bacteria that can cause food poisoning. Listeriosis symptoms include diarrhea, nausea, and fever. Pregnant...
Low Blood Pressure (Hypotension) Causes, Symptoms, Signs, Readings, and Treatments
Low blood pressure, also referred to as hypotension, is blood pressure that is so low that it causes symptoms or signs due to the...
Malaria is a disease that is spread by the bite of an infected Anopheles mosquito. Malaria symptoms include fever, chills,...
Marburg Virus Disease
Marburg virus disease is a zoonotic infection that produces symptoms such as chills, headaches, fever, and muscle aches. The...
Melanosis coli is a condition that is often associated with prolonged laxative use. Dark pigment forms in the wall of the large...
MERS (Middle East Respiratory Syndrome)
MERS-CoV (Middle East respiratory syndrome coronavirus) infection can be spread through respiratory secretions. Symptoms include...
Microscopic Colitis (Lymphocytic Colitis and Collagenous Colitis)
Microscopic colitis (lymphocytic colitis and collagenous colitis) is a disease of inflammation of the colon. Microscopic colitis...
Migraine headache is a type of headache associated with a sensitivity to light, smells, or sounds, eye pain, severe pounding on...
Munchausen Syndrome by Proxy (MSBP)
Munchausen syndrome by proxy (MSBP) is a mental illness (factitious disorder) in which a caregiver secretly abuses a child by...
Norovirus infection causes stomach flu, or gastroenteritis. It's a very contagious illness with symptoms that include nausea and...
Pancreatic Neuroendocrine Tumors (Islet Cell Tumors)
There are many types of pancreatic neuroendocrine tumors (NETs): gastrinoma, insulinoma, glucagonoma, VIPomas, and...
About 1% to 2% of people in the U.S. have a peanut allergy. Symptoms and signs of a peanut allergy include rash, hives, redness,...
Peritonitis is a bacterial infection inside of the abdomen. Some doctors choose to group the causes of peritonitis into five...
Primary Immunodeficiency Disease (PIDD)
Primary immunodeficiency disease or PIDD is a group of over 250 genetic diseases that involve the immune system. Symptoms of...
Q fever is a highly infectious disease that causes high fever, diarrhea, cough, and sweating. Infected animals may transmit Q...
Recreational Water Illnesses (RWI)
Recreational Water Illnesses (RWIs) are caused by germs spread by breathing in mists or aerosols, swimming, or having contact...
Roseola is a viral illness that most commonly affects young children. Symptoms and signs include a sudden high fever that lasts...
Rotavirus is the most common cause of severe diarrhea among infants and children throughout the world. Almost all children have...
Salmonella infection (salmonellosis) is typically caused by the consumption of contaminated foods. Symptoms of salmonellosis...
Severe acute respiratory syndrome (SARS) is a respiratory disease caused by the coronavirus SARS-CoV. Symptoms include fever and...
Shigellosis is a disease caused by the Shigella bacteria. Bloody diarrhea, stomach cramps, and fever are common symptoms. Mild...
Sick Building Syndrome
Multiple chemical sensitivity (MCS) or also referred to as sick building syndrome or environmental illness is the name given by...
STDs in Men
Sexually transmitted diseases (STDs) are infections transmitted during sexual contact. They may be caused by viruses, bacteria,...
Stomach Flu (Gastroenteritis) Symptoms, Signs Treatment Remedies, Diet
Stomach flu (gastroenteritis) is a term referred used to describe a variety of gastrointestinal problems. The most common signs...
Group A streptococcal infections are caused by group A streptococcus, a bacteria that causes a variety of health problems,...
Novel H1N1 influenza A virus infection (swine flu) is an infection that generally is transferred from an infected pig to a human,...
There are four major types of thyroid cancer: papillary, follicular, medullary, and anaplastic thyroid cancer. Tumors on the...
Toxic Shock Syndrome (TSS)
Toxic shock syndrome is an infection that causes symptoms such as low blood pressure, fever, and a rash with peeling skin....
Travelers should prepare for their trip by visiting their physician to get the proper vaccinations and obtain the necessary...
Travelers' diarrhea is generally contracted by eating contaminated food or drinking contaminated water. Food is the primary...
Typhoid fever is an illness caused by the Salmonella typhi bacteria. The illness is contracted by ingesting the bacteria in...
Typhus is a disease caused by Rickettsia bacteria. Symptoms and signs include fever, headache, nausea, vomiting, diarrhea, and...
Ulcerative colitis is a chronic inflammation of the colon. Symptoms include abdominal pain, diarrhea, and rectal bleeding....
Vibrio Infection (Vibriosis)
Vibrio bacteria thrive in warm coastal waters and cause illness when people eat undercooked shellfish or when brackish or...
Viral Hemorrhagic Fever
Viral hemorrhagic fever(s), or VHFs are a group of illnesses caused by distinct families of viruses. Many of these viruses are...
Other Causes of Diarrhea
- Bowel Resection
- Digestive Disorders
- Fecal Impaction
- Ischemic Bowel
- Medications (Both Prescription and Nonprescription)
- Parasites of Bowel
- Whipple Disease
Examples of Medications for Diarrhea
- attapulgite, Rheaban; Kaopectate Advanced Formula; Parepectolin; Diasorb; Diatrol; Donnagel
- diphenoxylate and atropine, Lomotil
- loperamide (Imodium)
- Metronidazole vs. Vancomycin
- Over-the-Counter Products
- sulfamethoxazole and trimethoprim, Bactrim, Bactrim DS
- tacrolimus (Prograf, Astagraf XL, Envarsus XR)
Subscribe to MedicineNet's General Health Newsletter