10 Common Causes Of Diarrhea

By Ashley Henshaw. May 7th 2016

Diarrhea is often considered to be an embarrassing and inconvenient condition that impedes with daily activities. While chronic bouts of diarrhea might indicate a serious health condition that requires consultation with a doctor, most cases of diarrhea can easily be avoided. Here are some common causes of diarrhea.


Sometimes, antibiotics used to treat infections can disrupt the normal flora in the intestines and cause an imbalance. Medications with antacid properties, or magnesium, can also cause a disruption of intestinal flora by killing off the “good bacteria.” In fact, the culprit behind serious cases of diarrhea is C. difficile, an organism that takes over the digestive tract when the normal flora is wiped out. Other medications and treatment therapies that irritate the digestive system can also list diarrhea as a side effect, so be sure to consult your doctor so you know what to expect.

Viruses And Parasites

Viruses like the rotavirus and Norwalk virus commonly cause diarrhea in younger children. While they cannot be treated with antibiotics or medication, the body usually recovers in a few days with plenty of rest and hydration. Parasites such as Giardia lamblia, Entamoeba histolytica, and Cryptosporidium are actual living protozoa organisms that survive by destroying the host. They can certainly give the host diarrhea, along with nausea and possibly vomiting. Be sure to follow the doctor’s orders for a speedy recovery.

Traveler’s Diarrhea

Traveler’s diarrhea is caused by organisms the body is not accustomed to, and usually happens when an individual ingests foods while traveling abroad. They are usually of a bacterial nature, though they can also be viruses or parasites. For example, E. coli and Salmonella have both gained popularity in the news when giving people “the runs.” Be sure to always ingest clean, uncontaminated water and food, and prepare the foods well and be sure they are thoroughly cooked.

Food Poisoning

Although our stomach acid can eliminate many harmful organisms upon contact, some may slip by and cause diarrhea. Food poisoning may cause signs and symptoms later on (as long as several days), which makes it hard to trace the origin. Be sure to seek immediate health care if you suspect diarrhea from food poisoning.

Lactose Intolerance

If you feel the urge to run to the toilet every time after eating dairy products (including ice cream), you may be lactose intolerant. Lactose intolerance is defined by the body’s inability to digest the sugars in dairy products, and is more common genetically in Asians than other ethnicities. Diarrhea due to lactose intolerance can also be accompanied by bloating and cramping. Fortunately, there are many milk alternatives on the market now, such as soy milk, almond milk, hemp milk, and coconut milk for your coffee and cereal.

Food Allergies

While lactose intolerance is the most common type of food allergy, other food allergies can also list diarrhea as a side effect in addition to other reactions, such as hives or rashes. For example, some people have trouble digesting fructose found in fruits, or artificial sweeteners found in packaged goods. For those that are allergic to gluten, diarrhea will most certainly happen if gluten is accidentally ingested.


For those who have just undergone a surgery, the stomach and bowels may not resume functions immediately. Aberrations from normal bowel movement, such as constipation or diarrhea, often accompany the recovering process from surgery. If a patient has specific abdominal surgery, or surgery involving the digestive tract, diarrhea may be more common due to the body’s inability to efficiently process foods. Be sure to consult with your health care provider and nurse on proper bowel movements, and whether having diarrhea is a normal sign post-surgery.

Stress And Diet

For those who have a very stressful lifestyle, or who have high anxiety levels, diarrhea may often accompany project deadlines and school examinations. Those who often eat harsh or irritating foods, such as excess alcohol, highly acidic coffee, or spicy foods, can also see an increase in diarrhea. Be sure to always take time to relax, and take a break from harsh foods every once in a while.

Digestive Disorders

When an individual is affected with disorders of the digestive system, diarrhea often becomes a sign or symptom of the underlying condition. Some digestive disorders that include diarrhea include Crohn’s disease, ulcerative colitis, celiac disease, irritable bowel syndrome, microscopic colitis and more.


Many cancer treatments, such as chemotherapy, radiation therapy or cell transplants, may cause adverse effects on the body and have diarrhea as a side effect. Cancers in the digestive tract are likely to list diarrhea as a symptom as well. Since chemotherapy decreases the patient’s immune system level, infections that cause diarrhea may also take place. Be sure to talk to your doctor about side effects of therapies so you know what to expect.

If your diarrhea lasts more than a day, and there is presence of blood in stool, be sure to seek medical help as soon as possible to rule out any life-threatening conditions.


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