Diarrhea: Causes, Symptoms, and Treatments

You may experience diarrhea because of several conditions or circumstances. Potential causes of diarrhea include:

• viral infections including rotavirus, norovirus, and viral gastroenteritis
• bacterial infections, including Salmonella and E. coli
• parasitic infections
• intestinal diseases
• a food intolerance, such as lactose intolerance
• an adverse reaction to a medication
• gallbladder or stomach surgery

Rotavirus is the most common cause of acute diarrhea globally. According to the Centers for Disease Control and Prevention (CDC), this infection causes around 40 percent of hospitalizations in children under 5 years old. Globally, most diarrhea deaths are the result of contaminated water supplies and insufficient sanitation.

In the United States, you are more likely to develop diarrhea due to food poisoning from eating contaminated foodstuffs. According to the CDC, annually there are close to 48 million diarrheal illnesses caused by contaminated food in the United States.

Chronic diarrhea may be a symptom of a more severe condition such as irritable bowel syndrome or inflammatory bowel disease. Frequent and severe diarrhea could be a sign of intestinal disease or a functional bowel disorder.

The main symptoms of diarrhea are frequent loose, watery stools and a pressing urge to have a bowel movement.

There are many different symptoms of diarrhea. You may experience only one of these or any combination of all of them. The symptoms depend on the cause. It’s common to feel one or more of the following:

• nausea
• abdominal pain
• cramping
• bloating
• dehydration
• a frequent urge to evacuate your bowels
• a large volume of stools
• dehydration

Dehydration and diarrhea

Diarrhea can cause you to lose fluids quickly and put you at risk for dehydration. If you don’t receive treatment for diarrhea, it can have severe effects. The symptoms of dehydration include:

• fatigue
• dry mucous membranes
• increased heart rate
• a headache
• lightheadedness
• increased thirst
• decreased urination
• dry mouth

Contact your doctor as soon as possible if you think your diarrhea is causing dehydration.

Learn more about dehydration here.

Diarrhea in babies and young children

Children are particularly susceptible to diarrhea and dehydration. The CDC reports that diarrhea and its complications account for around 1 in 9 annual child deaths worldwide, making this the second leading cause of death in those under age 5.

Call your child’s doctor or seek emergency care if you see symptoms of dehydration, such as:

• decreased urination
• dry mouth
• a headache
• fatigue
• a lack of tears when crying
• dry skin
• sunken eyes
• sunken fontanel
• sleepiness
• irritability

Research shows that the treatment for diarrhea typically requires replacing lost fluids. This means you need to drink more water or electrolyte replacement beverages, such as sports drinks.

In more severe cases, you may get fluids through intravenous (IV) therapy. If a bacterial infection is the cause of your diarrhea, your doctor may prescribe antibiotics.

Your doctor will decide your treatment based on:

• the severity of the diarrhea and related condition
• the frequency of the diarrhea and related condition
• the degree of your dehydration status
• your health
• your medical history
• your age
• your ability to tolerate different procedures or medications
• expectations for improvement of your condition

Your doctor will complete a physical examination and consider your medical history when determining the cause of your diarrhea. They may also request laboratory tests to examine urine and blood samples.

Additional tests your doctor may order to determine the cause of diarrhea and other related conditions can include:

• diet elimination tests to determine whether a food intolerance or allergy is the cause
• imaging tests to check for inflammation and structural abnormalities of the intestine
• a stool culture to check for bacteria, parasites, or signs of disease
• a colonoscopy to check the entire colon for signs of intestinal disease
• a sigmoidoscopy to check the rectum and lower colon for signs of intestinal disease

A colonoscopy or sigmoidoscopy is especially helpful for determining if you have an intestinal disease or severe or chronic diarrhea.

Although diarrhea can occur for various reasons, there are actions that you can take to prevent it:

• You can avoid developing diarrhea from food poisoning by washing the cooking and food preparation areas more frequently.
• Serve food immediately after preparing it.
• Refrigerate leftovers promptly.
• Always thaw frozen food in a refrigerator.

Preventing traveler’s diarrhea

You can help prevent traveler’s diarrhea by taking the following steps when traveling:

• asking your doctor if you can begin an antibiotic treatment before you leave
• avoiding tap water, ice cubes, and fresh produce that has probably been washed with tap water while you’re on vacation
• drinking bottled water only while on vacation
• eating cooked food only while on vacation

Preventing the spread of viral or bacterial infections

If you have diarrhea due to a viral or bacterial infection, you can prevent transmitting the infection-causing agent to others by washing your hands more frequently.

When you wash your hands, use soap and wash for 20 seconds. Use hand sanitizer when washing your hands isn’t possible.

Most cases of acute diarrhea are self-resolving, and symptoms will improve within a few days.

However, according to the National Institute of Diabetes and Digestive and Kidney Diseases, if symptoms persist for longer than 2 days, you should seek medical attention, as you may be getting dehydrated and need IV fluids or other treatment and evaluation.

Diarrhea is also a symptom of some serious medical emergencies. If you experience loose, watery stools alongside any of the following symptoms, you should seek emergency help. A combination of these symptoms may be a sign of a severe underlying illness.

• a fever
• bloody stools
• frequent vomiting

Seek immediate treatment if any of the following apply to your child:

• They’ve had diarrhea for 24 hours or more.
• They have a fever of 102°F (39°C) or higher.
• They have stools that contain blood.
• They have stools that contain pus.
• They have stools that are black and tarry.

These are all symptoms that indicate an emergency.

If you have diarrhea, you will typically experience loose, watery stools multiple times a day. You may also experience sudden urges to vacate your bowels.

Diarrhea is often the result of a short-term infection but can lead to severe complications, notably dehydration. The condition can also be chronic, although this is less common.

Viral and bacterial infections are the most common causes of diarrhea. Food intolerances, the side effects of medications, and underlying chronic conditions can also cause diarrhea.

If you experience symptoms for more than 2 days, you should see a doctor. If a child under your care is displaying symptoms of diarrhea, seek medical assistance immediately. Children under 5 years old are particularly susceptible to diarrhea and dehydration, and this is often a medical emergency.