Diarrhea is a condition characterized by loose, watery stools and abdominal cramps. Sufferers make numerous trips to the bathroom and pass a significant amount of stool, the Mayo Clinic says. These symptoms can last several days. Persistent diarrhea can lead to complications, such as dehydration. Sources of diarrhea that are considered to be the most common include viruses, bacteria and medication, the clinic says.
Viruses
There are a number of viral sources of diarrhea. Some of the most common viruses, as reported by the National Digestive Diseases Information Clearinghouse (NDDIC), include the Norwalk virus, cytomegalovirus, viral hepatitis and rotavirus in children. Viruses can spread from person to person and cause illness in anyone exposed. The virus tends to be found in fecal matter, so proper hygiene can limit the spread of the virus.
Bacteria and Parasites
Food and water can become contaminated with bacteria and parasites that cause diarrhea. Examples of such parasites include the Giardia lamblia and cryptosporidium. Bacterium responsible for the ailment include campylobacter, salmonella, shigella and Escherichia coli (E. coli). Foods and drink are infested with these infectious agents due to improper handling. Serving raw or undercooked foods and cross-contamination of foods are often to blame.
Medications
The most likely medications to cause diarrhea and stomach upset are antibiotics. They set off the natural balance of good and bad bacteria in the intestines. This can irritate the digestive tract and lead to an infection. Diarrhea caused by medication is temporary.
Other Common Causes
Food intolerances, such as dairy, can cause diarrhea and other abdominal symptoms. Some people may have an undiagnosed medical disease or disorder. This includes inflammatory bowel disease, colitis, Crohn's disease and celiac disease, the NDDIC says. The cause of each of these diseases is not fully understood, but medication can help control the symptoms.
