What Causes Watery Diarrhea?

Watery diarrhea is a bowel movement that’s loose and has the consistency of a liquid, like water. You can have watery diarrhea because of an infection, underlying health condition, food intolerance, or medication side effect.

While a short-term bout of diarrhea can usually resolve with a few days of at-home remedies like a bland diet and over-the-counter medications, diarrhea that lasts for a longer period of time can come with serious complications like dehydration.

Watery Diarrhea Symptoms

Diarrhea itself is a symptom that's generally defined as the passage of loose stool at least three times per day.

In addition to experiencing frequent liquid stool, you might also notice the following symptoms with watery diarrhea:

• Nausea and vomiting
• Bloating and gas
• Stomach cramping
• Fever and chills 
• Loss of appetite
• Blood in stool 
• Dizziness or lightheadedness
  

Causes of Watery Diarrhea

There are a variety of things that can cause watery diarrhea. Each cause may come with other symptoms, as well.

1. Infection

A common trigger for watery diarrhea is infection. The infection could be caused by a virus, bacterium, or parasite. Some of these germs are often transmitted through contaminated food or water, which can particularly happen when you're traveling to other countries.

Some of the most common germs that can lead to a infection and subsequent watery diarrhea include:

• Escherichia coli (or E. coli): Bacteria that commonly cause travelers' diarrhea
• Salmonella: Bacteria that can be contracted from raw or unwashed foods
• Shigella: Bacteria that are often transmitted in crowded spaces or spaces with poor sanitation practices
• Rotavirus: A virus that accounts for most diarrhea-related hospitalizations among children
  
• Norovirus: A virus that commonly causes foodborne illness
• Adenoviruses: A group of viruses that are linked to illnesses like the common cold but that can also cause diarrhea
  
• Giardiasis: A parasite that is contracted through contaminated food or water or contact with animal feces
  

Infectious causes of diarrhea are usually shorter in length—meaning they last for less than two weeks. You may also experience other symptoms typical of an infection, like nausea, vomiting, stomach cramping, fever, headache, and body aches.

2. Food Intolerance

For some people, exposure to certain types of foods and ingredients can cause watery diarrhea. Sweeteners and sugars in particular may be ingredients that lead to liquid stools—in these cases, the body can't properly absorb carbohydrates.

Ingredients to which people may be sensitive and that may lead to watery diarrhea include:

• Lactose: A type of sugar that’s naturally in milk and dairy products
• Fructose: A sugar found in fruits and honey 
• Artificial sweeteners: Examples include mannitol and sorbitol mannitol and xylitol, which are found in gum, soft drinks, and sugar-free candy
• Gluten: A protein in certain grains like wheat

If certain types of food or ingredients cause watery diarrhea, you may also experience other food intolerance symptoms like bloating and excessive gas after consuming the products. In general, these cases are considered to be chronic (or long-lasting), lasting four weeks or longer.

3. Health Condition

Experiencing watery diarrhea on a regular basis can be a symptom of an underlying health condition.

For example, diabetes may trigger diarrhea because of nerve damage and bacterial overgrowth in the digestive tract. This usually happens when diabetes has been long-lasting or isn't well-controlled.

There are many digestive conditions that are often associated with watery diarrhea, too. This includes irritable bowel syndrome (IBS), celiac disease, and inflammatory bowel disease (IBD). With these conditions, you may also notice symptoms like bloating and stomach pain that's relieved after having a bowel movement.

4. Medication Side Effect

Certain types of medications have watery diarrhea as a side effect. Medications that can cause watery diarrhea include:

• Antibiotics
• Antacids
• Non-steroidal anti-inflammatory drugs (NSAIDs)
• Antiarrhythmics (medications that manage abnormal heart rhythms)
• Chemotherapy drugs used for cancer
• Laxatives that contain magnesium

Some vitamins and supplements can also trigger watery diarrhea.

Complications of Watery Diarrhea

Some cases of watery diarrhea resolve on their own within a day or two. But sometimes, watery diarrhea can lead to serious complications. 

The most common complication of watery diarrhea is dehydration. Dehydration can occur when the body doesn’t have enough fluid to function, leading body systems and organs to malfunction. Losing so much fluid that you become dehydrated can lead to seizures, kidney failure, and shock, which may be life-threatening in severe cases.

It’s also possible to experience malabsorption with watery diarrhea. This is when your body isn’t able to absorb enough essential nutrients from the food you eat, leading to malnourishment or malnutrition. Symptoms of malabsorption include bloating, gas, unintended weight loss, changes in appetite, and loose stools that may appear oily and smelly.

When To See a Healthcare Provider

If you’re experiencing any watery diarrhea episodes that last longer than two days, it’s a good idea to seek medical care. Children or babies shouldn’t wait more than 24 hours to get medical care, as they’re more susceptible to complications from diarrhea. 

You should seek urgent medical care if your watery diarrhea is accompanied by any of the following:

• High fever
• Severe stomach pain
• Bloody or black stool
• Signs of dehydration, like extreme thirst, dark-colored urine, fatigue, and dry mouth

You can expect a healthcare provider to perform a physical examination, which can include checking your temperature, blood pressure, and abdominal area. They'll likely ask about the details of your watery diarrhea, including how long it’s been happening, whether you’ve traveled recently, what the diarrhea looks like, and if you have a personal or family history of any digestive conditions.

From there, a healthcare provider may run some diagnostic tests to help them determine the underlying cause of your issue. This might include a stool test to check for parasites or bacteria, a blood test to look at any signs of infection or disease, a breath test if lactose intolerance is suspected, or a rectal exam to check the inside of your rectum.

Imaging tests like a colonoscopy or upper endoscopy to take a look at the inside of your digestive system may also be ordered. And if a dietary issue is suspected, a fasting test might be recommended, where you follow an elimination diet to cut out any foods like dairy or wheat that may be causing diarrhea in certain health conditions. 

Treatments for Watery Diarrhea

Treatment may depend slightly on the root cause of your watery diarrhea, but the goal regardless of the cause will be to stop the diarrhea and replenish any fluids that have been lost to prevent dehydration. 

Some treatment options of watery diarrhea include:

• Home remedies: Eating bland foods like bread, crackers, and bananas can be easier on your stomach as you recover. Avoiding caffeine as well as spicy or fried foods until symptoms resolve may also help. Getting lots of rest and staying hydrated by drinking plenty of fluids, particularly drinks with electrolytes like Gatorade, is also key. 
• Over-the-counter medications: Antidiarrheal drugs like Pepto-Bismol (bismuth subsalicylate) and Immodium (loperamide) can help slow down your bowel movements temporarily. 
• Prescription medications: A healthcare provider may recommend antibiotics if you have a bacterial infection. If a chronic digestive condition is diagnosed, there are prescription medications available that can help manage the disease and reduce symptoms.

How To Prevent Watery Diarrhea

It's not always possible to avoid watery diarrhea. Some cases of diarrhea can be prevented with the following tips:

• Be mindful of what you eat, especially while traveling: Avoiding raw foods and consuming items that have been well-cooked are key. In addition, make sure food you're consuming has been stored at the correct temperature. You can also consider using bottled water for drinking and teeth brushing while traveling.
• Practice good hygiene: Keeping your hands washed with warm water and soap (or a hand sanitizer if a sink is unavailable) will help keep germs at bay. Especially make sure to wash hands before and after eating or handling food, as well as after using the bathroom, sneezing, or coughing. 
• Consider taking probiotics and zinc supplements: Probiotic supplements or yogurt containing probiotics (which are healthy bacteria that keep the gut’s bacterial environment balanced) may be helpful. A healthcare provider may suggest taking in probiotics if you are prescribed antibiotics. Some research has shown that taking a zinc supplement may help prevent and treat short-term diarrhea cases.

A Quick Review

Watery diarrhea is defined as having loose, liquid-like stools several times per day. This can happen due to an infection, food intolerance, health conditions, or medication side effects. While many cases of watery diarrhea resolve in a couple of days with at-home remedies like a bland diet, rehydration, and over-the-counter medications, severe cases of watery diarrhea can result in complications like dehydration if left untreated.

Get urgent medical care if you have watery diarrhea and notice symptoms like fever, dark-colored urine, severe stomach pain, or bloody stool.