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Watery Diarrhea Symptoms, Causes & Common Questions

Watery diarrhea is commonly caused by a viral infection or food poisoning from eating undercooked meat or rotten foods. It can be serious if it causes dehydration. Keep an eye out for blood in the stool, and be sure to drink water and fluids with electrolytes.
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7 most common causes

Norovirus
Food Poisoning
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Diarrhea
Microscopic Colitis
Rotavirus
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Shigella infection
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Intestinal infection with ameba parasite

Watery diarrhea symptoms explained

Watery diarrhea is a common sign of an intestinal infection, but can also be caused by chronic conditions like inflammatory bowel disease or irritable bowel syndrome. For most people, watery diarrhea is only dangerous if it causes severe dehydration.

As the body gets rid of the infection and repairs the walls of the intestines, symptoms should get better within a week or two. Most people can treat diarrhea at home.

It is important to watch for blood in stool and to continue to consume both water and electrolytes to replace the fluid lost through diarrhea.

See a doctor if you cannot replace fluids, feel dizzy, or your symptoms are severe or last more than 2–3 days.

Symptoms of watery diarrhea

Watery diarrhea may include the following symptoms.

Treatment for watery diarrhea

Treatments for watery diarrhea vary widely, though they all have the same starting point: Stay hydrated. Depending on the cause of watery diarrhea and how long it lasts, you may need to take antibiotics or undergo a colonoscopy to examine your intestines for signs of inflammatory disease.

  • Antibiotics: These are taken for bacterial and protozoal causes. You will not receive antibiotics for a viral cause of diarrhea. If your symptoms do not improve within a week of taking antibiotics, you should call your doctor and ask whether you need to make an appointment.
  • Diagnostic workup: You may need to have some tests if you have diarrhea that is not caused by an infection and doesn’t go away after a couple weeks. This may include taking a stool sample that will be examined under a microscope to look for any pathogens or signs of inflammation.
  • Dietary restriction: If you have irritable bowel syndrome, it may be helpful to avoid certain foods. Foods containing lactose may be indigestible and cause chronic diarrhea, and other foods may cause an allergy that damages the gut and leads to symptoms of irritable bowel syndrome. The process of eliminating foods usually takes a longer period of time, and involves cutting out many foods and slowly adding in foods one at a time to determine what you can tolerate.

Seek immediate treatment for the following

You should seek help without delay if:

  • You have an inability to replace the fluids you are losing
  • You feel dizzy, lightheaded or lose consciousness
  • You do not improve on antibiotics
  • You have symptoms for longer than two days
  • You have a recurrence of symptoms without being exposed to the same initial cause

Watery diarrhea quiz

Take a quiz to find out what's causing your watery diarrhea.

Take watery diarrhea quiz

What causes watery diarrhea?

Acute causes

Acute causes are those that come on suddenly and go away in about 1–2weeks. These forms of diarrhea are usually caused by an infection. They can be caused by viruses, bacteria, or protozoas. Accordingly, the treatment for most infectious diarrhea is supportive care with some variations, such as whether you need to take an antibiotic, which will depend on your specific case and stamina.

  • Viruses: Viruses are usually not life-threatening and there are a wide array of viruses that cause diarrhea in different parts of the world and in different seasons. Common types of viruses include norovirus, adenovirus, astrovirus, and rotavirus. They can easily spread in enclosed spaces like cruise ships or college dorms. In all but the very young, very old, and immunosuppressed, they are not life-threatening. If you think that you have a virus that is causing diarrhea, stay hydrated with soups, broths, and electrolyte drinks and get plenty of rest. Remember to wash your hands and keep your living areas sanitized and tidy so the illness doesn't spread to your house or roommates.
  • Bacteria: Bacteria are also rarely life-threatening, but in some select cases, can cause more severe diarrhea or can affect other organ systems. Common bacteria include salmonella, campylobacter, shigella, E. Coli, and Clostridium difficile. Most of these types of bacteria will get better on their own but you may need antibiotics for some.
  • Protozoa: Protozoa are often treated with antibiotics even though the body can frequently eliminate protozoa without treatment. Treatment in most cases shortens the duration, and, importantly, the transmission of the disease to other individuals. Giardia, a type of bacteria that occurs when drinking fresh, untreated water from streams, or lakes, is treated with antiprotozoal agents. However, in some cases like Cyclospora, diarrhea can continue for months and it is treated primarily to shorten the duration of infection.

Chronic causes

Chronic causes of watery diarrhea are those that are longer-lasting or more difficult to treat and may require hospitalization.

  • Chronic infections (C. Difficile, Campylobacter): Some infections like C. difficile occur in part because of treatment for other diseases. C. difficile is a bacteria that lives peacefully in a normal bowel as it is often kept at low levels by normal gut bacteria. However, if you’re taking antibiotics or have a suppressed immune system, C. difficile may grow unchecked. Often treatment of C. difficile requires hospitalization for monitoring and proper treatment to avoid dangerous levels of dehydration. It is often (but not always) first treated with the antibiotic vancomycin.
  • Inflammatory bowel disease: This can affect either the small intestine, large intestine, or both. It may produce watery diarrhea, bloody diarrhea, mucus-laden diarrhea or a mixture of the three. It is commonly treated with drugs that temper and lower the immune response. If you have long-standing watery diarrhea that does not respond to antibiotics, you may have inflammatory bowel disease or irritable bowel syndrome. However, a proper diagnosis will require a colonoscopy (or a scope usually inserted through the anus) to examine the walls of the intestines.
  • Irritable bowel syndrome: This can have many different kinds of symptoms. It can cause constipation (IBS-C), diarrhea (IBS-D), or mixed (IBS-M). Irritable bowel syndrome with diarrhea also causes abdominal pain or discomfort.  Treatments vary widely from avoiding food triggers and lactose and increasing consumption of fiber and physical activity levels. IBS is only diagnosed after inflammatory bowel disease or cancer has been ruled out.

Food poisoning

Food poisoning, also called foodborne illness or "stomach flu," is an acute infection of the digestive tract from food contaminated with bacteria, viruses, parasites, or other toxins. It actually has no relation to influenza.

Any food can become contaminated if not prepared under clean conditions, cooked thoroughly, or stored at cold temperatures. Meat, fish, dairy products, and fresh fruits and vegetables are some of the most easily contaminated foods.

Symptoms include nausea, vomiting, diarrhea, and abdominal pain, and sometimes fever and chills.

Most people recover on their own with supportive care, meaning rest, fluids, and over-the-counter pain relievers and fever reducers.

However, dehydration can result if the vomiting and/or diarrhea are not controlled and IV fluids may be needed.

If there is also blurred vision, dizziness, or paralysis, the nervous system may be affected due to botulism. This is a medical emergency. Take the patient to the emergency room or call 9-1-1.

Proper food preparation and storage, along with frequent and thorough handwashing, is the best prevention.

Rarity: Common

Top Symptoms: nausea, abdominal pain (stomach ache), headache, abdominal cramps (stomach cramps), dizziness

Symptoms that never occur with food poisoning: severe fever, being severely ill, bloody diarrhea

Urgency: Self-treatment

Diarrhea caused by a bacteria called vibrio

The Vibrio genus of bacteria causes nausea, vomiting, and diarrhea that can be very serious. Vibrio parahaemolyticus and Vibrio vulnificus are two of the species that cause this illness, which is also called vibriosis.

The primary risk factor is eating raw or undercooked seafood, especially oysters from any coastal waters and from the Gulf of Mexico in particular. People with weakened immune systems or liver disease are especially vulnerable to this infection.

Symptoms include fever, vomiting, and diarrhea, sometimes with mental confusion. These symptoms in a person who has recently eaten raw seafood, or has been swimming in ocean or bay water, are considered a medical emergency. Take the patient to the emergency room or call 9-1-1.

Some types of Vibrio-caused illness can worsen very quickly and lead to dehydration and septicemia, which can be life-threatening.

Diagnosis is made through patient history, physical examination, and lab tests on blood, urine, and stool samples.

Treatment will usually involve hospitalization for intravenous fluids, antibiotics, and supportive care.

Rarity: Rare

Top Symptoms: diarrhea, nausea, stomach bloating, headache, abdominal cramps (stomach cramps)

Symptoms that always occur with diarrhea caused by a bacteria called vibrio: diarrhea

Urgency: Self-treatment

Viral (norovirus) infection

Norovirus infection is caused by the highly contagious Norwalk virus. It spreads when any trace of stool or vomit from an infected person contaminates food or drink, or gets onto any surface. Anyone who consumes the food or drink, or touches the surface and then their mouth, will become infected.

Norovirus brings on severe gastrointestinal upset which is very unpleasant but rarely dangerous. Symptoms include diarrhea, vomiting, stomach pain, fever, and body aches for one to three days. The greatest risk is dehydration due to the severity of the symptoms.

Because norovirus is, indeed, a virus, antibiotics will not help. The best treatment is good supportive care, which means providing plenty of fluids along with mild pain relievers until the patient recovers. Do not give aspirin to children.

If the dehydration does not improve quickly, medical help should be sought. Doctors can provide IV fluids through recovery.

The best prevention is frequent and thorough handwashing, as well as washing all fruits and vegetables. All foods must be properly cooked, especially shellfish.

Traveler's diarrhea

Traveler's diarrhea is a digestive tract disorder that commonly causes loose stools and abdominal cramps. It's caused by eating contaminated food or drinking contaminated water.

You can safely treat this condition by drinking lots of fluids to avoid dehydration. Taking an antidiarrheal medication such as loperamide (Imodium) may help as well.

Rarity: Common

Top Symptoms: diarrhea, nausea, abdominal pain (stomach ache), fever, stomach bloating

Symptoms that always occur with traveler's diarrhea: diarrhea

Symptoms that never occur with traveler's diarrhea: anxiety

Urgency: Self-treatment

Shigella infection

Shigella infection, or shigellosis, is an intestinal infection caused by a strain of Shigella bacteria.

Shigellosis is highly contagious through fecal matter. Anyone coming into contact with any trace of feces in food, drink, or surfaces can get the disease. Swimming in contaminated water, even in a chlorinated pool or hot tub, is another source of infection.

Most susceptible are young children; travelers to less developed regions; and anyone with a weakened immune system.

Symptoms include fever; abdominal pain and cramps; and severe diarrhea, which may contain blood.

If not treated, there is the risk of dehydration due to the diarrhea and fever. Young children are especially susceptible.

Diagnosis is made through patient history, physical examination, and testing of a stool sample.

Treatment involves rest and fluids. Most cases clear up within a week. Sometimes antibiotics are used in more severe cases, though antibiotics are not effective against some forms of Shigella bacteria.

The best prevention is frequent and thorough handwashing, and good hygiene when preparing food.

Rarity: Rare

Top Symptoms: diarrhea, general abdominal pain, severe diarrhea, watery diarrhea, fatigue

Symptoms that always occur with shigella infection: diarrhea

Urgency: Self-treatment

Normal occurrence of diarrhea

Diarrhea can be an indication of serious illness – especially in young children – but in some cases it has a much simpler cause and can be easily cured.

If there are simply frequent loose stools – three or more times per day – without other symptoms of illness, the most common cause is food or drink.

Overuse of caffeine, beer, or wine has a laxative effect on some individuals. The artificial sweeteners sorbitol and mannitol are known laxatives, as are some herbal supplements and some over-the-counter vitamin and mineral preparations.

Lactose intolerance, or the inability to digest the natural sugar in milk, causes digestive upset and diarrhea.

Diarrhea can cause dehydration and mineral imbalance no matter what the cause, so it is still important to manage it.

The best treatment is to remove some items or supplements from the diet and watch the results. This will show which items are causing the diarrhea.

It's always wise to use any new supplements in moderation so that if the trouble recurs, the cause will be plain.

Rarity: Common

Top Symptoms: diarrhea, mild diarrhea

Symptoms that always occur with normal occurrence of diarrhea: diarrhea

Symptoms that never occur with normal occurrence of diarrhea: bloody diarrhea, severe diarrhea, worsening diarrhea, being severely ill, ill appearance

Urgency: Self-treatment

Microscopic colitis

Microscopic colitis is caused by inflammation of the large intestine than can only be seen with a microscope. It is believed that microscopic colitis is caused by an overly aggressive immune response to a certain trigger that can be related to medication, an infection, autoimmune diseases, genetics, or a malabsorption of bile.

Symptoms primarily include watery diarrhea accompanied by abdominal pain, cramps or discomfort, and an urgency to use the restroom.

Treatment depends on the cause, such as halting offensive drugs and taking anti-diarrheal medication or steroids. It is also important to make sure you stay hydrated throughout the recovery period.

Rarity: Rare

Top Symptoms: fatigue, nausea, diarrhea, abdominal pain (stomach ache), stomach bloating

Symptoms that always occur with microscopic colitis: diarrhea

Symptoms that never occur with microscopic colitis: bloody diarrhea

Urgency: Primary care doctor

Intestinal infection with ameba parasite

Visiting or living in places with poor sanitation can lead to parasite infections that can cause long-lasting diarrhea and stomach pain.

You should go see a primary care physician (PCP) soon. Diagnosing parasite infections reuires stool samples at a PCP, and its treatment involves prescription anti-parasitic medications that a PCP would then prescribe.

Rarity: Rare

Top Symptoms: nausea, loss of appetite, diarrhea, constipation, general abdominal pain

Urgency: Primary care doctor

Watery diarrhea quiz

Take a quiz to find out what's causing your watery diarrhea.

Take watery diarrhea quiz

Food poisoning by the staphylococcus bacteria

Food poisoning, also called foodborne illness or "stomach flu," is an acute infection of the digestive tract from food contaminated with bacteria, viruses, parasites, or other toxins. It actually has no relation to influenza.

Any food can become contaminated if not prepared under clean conditions, cooked thoroughly, or stored at cold temperatures. Meat, fish, dairy products, and fresh fruits and vegetables are some of the most easily contaminated foods.

Symptoms include nausea, vomiting, diarrhea, and abdominal pain, and sometimes fever and chills.

Most people recover on their own with supportive care, meaning rest, fluids, and over-the-counter pain relievers and fever reducers.

However, dehydration can result if the vomiting and/or diarrhea are not controlled and IV fluids may be needed.

If there is also blurred vision, dizziness, or paralysis, the nervous system may be affected due to botulism. This is a medical emergency. Take the patient to the emergency room or call 9-1-1.

Proper food preparation and storage, along with frequent and thorough handwashing, is the best prevention.

Rarity: Uncommon

Top Symptoms: nausea, nausea or vomiting, diarrhea, abdominal cramps (stomach cramps), vomiting

Symptoms that always occur with food poisoning by the staphylococcus bacteria: nausea or vomiting

Urgency: Self-treatment

FAQs about watery diarrhea

Here are some frequently asked questions about watery diarrhea.

What causes watery diarrhea?

Watery diarrhea can be caused by an inability to absorb the water that you drink, the water in food, or the secretion of water from the gut following infection or consumption of something that pulls water from the gut. Common examples are consumption of excess lactose or xylose sugars that are not easily digested as well as cholera.

How do you know when to seek care for dehydration?

If you feel faint, dizzy, or nauseous, or have lost consciousness, you may be dangerously dehydrated. A lack of fluids can cause low blood pressure, confusion, or a loss of consciousness if it is severe. Kidney failure can also occur if a loss of fluid is especially rapid. If you stop urinating for an extended period of time, you should be concerned about potential kidney injury.

When should you seek medical care for watery diarrhea?

If you find blood or mucus in your diarrhea, if you have difficulty maintaining adequate hydration either because of nausea or because of excessive or continuous liquid diarrhea, if you lose consciousness, become confused, stop sweating, or stop urinating you should seek care immediately.

How long does watery diarrhea usually last?

Watery diarrhea can last anywhere from a few days to a few weeks. Often even severe watery diarrhea can and will resolve on its own. It is important, however, to maintain adequate hydration. Diarrhea from a dietary cause will continue until the substance has left your system. Diarrhea from a toxin or from an infection will continue until the body clears the infection or it is treated with antibiotics.

What are some other symptoms of watery diarrhea that may be more dangerous?

Blood in your diarrhea, mucus, completely watery diarrhea, a loss of color in your stool, large amounts of mucus, or symptoms of dehydration may be signs that you should seek urgent or emergent evaluation for complicated abdominal pain or dehydration.

Questions your doctor may ask about watery diarrhea

  • Any fever today or during the last week?
  • Have you experienced any nausea?
  • Have you been feeling more tired than usual, lethargic or fatigued despite sleeping a normal amount?
  • Have you lost your appetite recently?

Self-diagnose with our free Buoy Assistant if you answer yes on any of these questions.

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Dr. Rothschild has been a faculty member at Brigham and Women’s Hospital where he is an Associate Professor of Medicine at Harvard Medical School. He currently practices as a hospitalist at Newton Wellesley Hospital. In 1978, Dr. Rothschild received his MD at the Medical College of Wisconsin and trained in internal medicine followed by a fellowship in critical care medicine. He also received an MP...
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References

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