A variety of conditions can cause diarrhea. Contamination of food and drinks by bacteria, viruses, or parasites; reactions to medications such as antibiotics; food poisoning and food intolerance are some of the causes of diarrhea⁴.
Diarrhea also happens when the balance of microbes in the gut is disrupted , which means the bad bacteria or those diarrhea causing ones outnumber the good bacteria, or those that help fight the infections⁸.
Usually, diarrhea is caused by a virus found in human feces⁹. People mistakenly called it “stomach flu”¹⁰. Four leading diarrhea-causing viruses are rotavirus, norovirus, adenovirus and astrovirus¹¹.
With this gut-brain connection, people with gastrointestinal (GI) problems often experience anxiety and stress brought by the condition. On the other hand, anxiety and stress can make GI problems worse²².
Bacteria and parasites from contaminated food and water (food poisoning) can also cause diarrhea⁸. Bacteria are responsible for the most severe cases of infectious diarrhea than other causes¹².
Sometimes no cause can be found. As long as diarrhea goes away within 1 to 2 days, finding the cause is usually not necessary⁴.
Aside from preventing dehydration by replacing lost fluids, salts, and minerals, it is also important to treat the underlying cause of diarrhea—the imbalance of good and bad microorganisms in your gut⁸. Probiotics are friendly bacteria and yeasts which can stop the growth of infection causing bacteria and restore the body’s good versus bad bacterial balance⁸.