What Causes Diarrhea? 4 Possibilities

Diarrhea occurs when you have loose, watery bowel movements. Bacteria, viruses, and other microbes that lead to infection can cause acute diarrhea, which can last a day or so. Chronic diarrhea, which lasts for weeks, may be due to causes such as irritable bowel syndrome (IBS) or medication side effects.

Diarrhea may occur based on the foods you eat. For example, raw or contaminated foods or dairy products with lactose—if a person is lactose intolerant—can be problematic. Read on to learn more about what causes diarrhea and when to see a healthcare provider.

1. Bacteria

Food contamination is one of the main ways bacteria, viruses, and parasites enter your system to make you sick and cause diarrhea. Bacteria like E. coli, Salmonella, Campylobacter, Shigella, and Listeria can be found in foods that are not refrigerated well enough. You might also find them in:

• Eggs
• Raw and undercooked meats and shellfish
• Raw vegetables
• Unpasteurized milk
  

2. Viral Infections

Viruses are another major culprit in causing acute diarrhea, and they make it into your body much in the same way as bacteria. Norovirus is probably the most common of the diarrhea-causing viruses. These stomach bugs usually leave your system in a few days, but not without symptoms like vomiting, abdominal pain, and diarrhea.

3. Parasites

Parasites are small organisms that, like viruses and bacteria, can infect food and water and end up in your system after you've eaten or drank contaminated foods or drinks. For example, you may find parasites in raw or undercooked fish or undercooked beef and pork. Common infectious parasites are Cryptosporidium, Entamoeba histolytica, and Giardia.

4. Running

Although scientists don't know why it happens, there's lots of anecdotal evidence of the running poops, or "runner's diarrhea." GI symptoms like diarrhea can happen during a run for a few reasons. It's suggested that stress hormone release, movement of bacteria in the intestinal tract, and inflammation within the GI tract may be responsible.

What Causes Chronic Diarrhea?

Chronic diarrhea, on the other hand, typically isn't caused by infection. Chronic diarrhea can happen for many reasons, such as:

• Endocrine disorders: Endocrine disorders—which are sometimes more commonly known as hormone imbalances—are another common cause of diarrhea. Examples are diabetes, hyperthyroidism, and Addison's disease, when your body doesn't produce enough cortisol and other hormones from your adrenal gland.
• Food intolerance: Most of the time, diarrhea caused by foods happens because of malabsorption—meaning you don't have enzymes to break down the food. An example is not having the enzymes to break down gluten or sugars like lactose or fructose.
• Inflammatory bowel disease (IBD): Inflammatory bowel disease, or IBD, is often confused with IBS. However, it consists of Crohn's disease and ulcerative colitis (UC). The digestive tract becomes inflamed in both conditions, reducing its ability to absorb and deliver nutrients.
• Irritable bowel syndrome (IBS): IBS is a gastrointestinal disorder that refers to a collection of symptoms often occurring together, like bloating, diarrhea, constipation, and general stomach discomfort.
• Laxative use: Using laxatives frequently can result in chronic diarrhea.
• Medications: Antibiotics, diabetes medications, cancer drugs, antacids that contain magnesium, and nonsteroidal anti-inflammatory drugs (NSAIDs) can also cause GI problems, including diarrhea.
  

Risk Factors

Some individuals may be more at risk of developing diarrhea. Risk factors include:

• Diagnosis of GI-related conditions
• Exposure to infectious germs
• Travel to developing countries
• Use of certain medications like antibiotics
• Weakened immune system

Treatment

The majority of acute diarrhea cases can be treated at home. Some people may be able to take over-the-counter medications to help with diarrhea. However, you should only do so with a healthcare provider's guidance. You can also:

• Avoid dairy products if you have severe diarrhea, as well as alcohol, caffeine, or fizzy drinks.
• Drink water daily and at least one cup of liquid every time your bowel movement is loose.
• Eat smaller meals throughout the day.
• Eat salty and high-potassium foods for electrolytes.

The causes of chronic diarrhea will guide treatment. A healthcare provider may prescribe antibiotics or medications to treat the health condition causing the diarrhea, if applicable.

How To Prevent Diarrhea

There are various ways to prevent infectious or non-infectious diarrhea. You can:

• Cook and store foods properly.
• Clean before, during, and after food preparation.
• Drink bottled water and avoid undercooked or raw foods when traveling to developing countries.
• Use alcohol-based hand sanitizer when soap and water aren't available.
• Wash your hands regularly, including after a visit to the restroom, before you eat, and before and after handling or preparing food.

When To Contact a Healthcare Provider

There are a few reasons to see a healthcare provider if you have diarrhea. Contact a provider if you experience:

• Black stools
• Blood or pus in your stool
• Diarrhea after traveling to a foreign country
• Diarrhea with a fever of 101 degrees Fahrenheit or higher
• Persistent or worsening diarrhea after five days
• Persistent stomach pain following a bowel movement
• Signs of dehydration, like dry mouth and decreased urine

A Quick Review

Acute diarrhea may be caused by different germs or running, while chronic diarrhea can result from certain GI conditions or medications. You can usually treat most cases of diarrhea with home remedies, but chronic cases can require prescriptive treatment from a healthcare provider. Also, see a healthcare provider if your diarrhea doesn't get better with treatment or if you have symptoms like black stools, stomach pain, or dehydration signs.