Diarrhea, simply put, is loose, watery stools. The National Digestive Diseases Information Clearinghouse (NDDIC) states that people of any age can suffer from diarrhea, with the average adult suffering from acute diarrhea (diarrhea lasting only one or two days) about four times a year. Diarrhea is caused by a variety of reasons, some of which are indicate an underlying medical condition.
Viruses
Both the Mayo Clinic and the NDDIC agree that the most common cause of diarrhea are viruses. These include the Norwalk virus, viral hepatitis, cytomegalovirus and the herpes simplex virus.
Among children, the rotovirus is the most common cause. This causes an infection in the intestines.
Bacterial Infections
Eating contaminated food or drinking water containing bacteria or parasites can spark an episode of diarrhea. The Mayo Clinic states that the most common bacterial causes include but are not limited to salmonella and E. coli, while common parasites include Giardia lamblia and cryptosporidium.
People at greatest risk for diarrhea due to these causes are those who travel to developing countries. These countries typically do not have proper filtration systems nor do they use the process of pasteurization. This is often referred to as traveler's diarrhea.
Medications
In some cases, the medication you are taking may cause diarrhea. Jackson Siegelbaum Gastroenterology, a practice located in Pennsylvania specializing in diseases of the digestive system, states that antibiotics are the most common cause of diarrhea among medications. This is because antibiotics destroy bad bacteria in the body. In the process, they also destroy good bacteria, throwing off the balance in the intestines.
Lactose Intolerance
Those who have a milk allergy, also known as lactose intolerance, are prone to episodes of diarrhea. Persons with this allergy are usually so sensitive to the milk sugar lactose that even the smallest amounts can cause the abdominal pain and bouts of loose stools. Aside from milk, persons with this allergy typically cannot eat any milk products with the exception of yogurt.
Gallbladder Surgery
The NDDIC states that persons who have undergone gallbladder surgery may be at higher risk for suffering from diarrhea. This may be because food moves much faster through the digestive system or because of the increase of bile in the colon once the gallbladder has been removed.
