Diarrhea is an increase in the frequency of loose or liquid bowel movements. Acute diarrhea is suspected if a person presents with 3 or more loose, watery, or bloody stools within 24 hours. On the other hand, persistent or chronic diarrhea is suspected if these symptoms last for at least two weeks or a month, respectively.

Acute diarrhea is usually a symptom of a gastrointestinal infection, which can be caused by a variety of bacterial, viral, and parasitic organisms. These are usually transmitted through ingestion of contaminated food and water.

Persistent or chronic diarrhea, on the other hand, may be caused by various problems, including problems in water or nutrient absorption, surgical procedures (like colon surgery), certain medications like some antibiotics, difficult digestion (from problems in the liver or pancreas), irritable bowel syndrome, and inflammatory bowel disease.

By definition, patients with diarrhea experience the passage of watery stools at least 3 times a day. This can be accompanied by fever, nausea, and vomiting. Due to the loss of body fluids, these patients also often experience dehydration, which presents as:
• Excessive thirst;
• Dizziness;
• Confusion or disorientation;
• Decreased urine output;
• Sunken eyeballs;
• For infants: Sunken soft spots in the skull.

Individuals with mild to moderate dehydration can be given Oral Rehydration Solution (ORESOL) to replace lost body fluids; more severe cases may require rehydration to be done intravenously. Anti-motility medications, like loperamide, which may reduce stool frequency can be given, except if there is bloody stool, fever, or abdominal pain, or if the patient is a child or infant.

Since most community-acquired diarrhea is viral in nature, the use of antibiotics is generally discouraged, unless the patient is immunocompromised or if there is strong clinical suspicion for a bacterial infection.

As for persistent or chronic diarrhea, further tests to identify the cause are usually done to be able to address the underlying problem and treat the diarrhea.

Individuals can avoid getting diarrhea, especially infectious diarrhea, by:
• Practicing hand hygiene regularly, especially before eating and after using the toilet.
• Drinking water only from safe sources. If unsure, boil drinking water for 3 minutes or do water chlorination.
• Washing fruits, vegetables, meat, and fish with clean water before eating or cooking.
• Separating meat, poultry, vegetables, and fish to avoid contamination.
• Eating only food that is well cooked and properly prepared.
• Keeping food away from insects and rats by storing or covering them properly.
• Using the toilet properly.

In addition, children may benefit from vitamin A and zinc supplementation, as well as the use of probiotics like Lactobacillus products, as these have been shown to reduce the risk of diarrhea among children.