What Causes Gastroenteritis?

Bacteria, viral infections and parasites are the most common causes of gastroenteritis, also known as the stomach flu, according to Merck Manuals. In rare cases, gastroenteritis is caused by ingesting toxic chemicals or reacting adversely to medicinal drugs.

Gastroenteritis is inflammation of the stomach and intestines that leads to vomiting, stomach pain, diarrhea, fever and nausea, states WebMD. When caused by viral infections, such as rotovirus or norovirus, the condition often spreads from person to person through skin contact when individuals don’t wash their hands carefully. Bacteria, such as salmonella and E. coli, are usually transmitted through contaminated food, including undercooked eggs and poultry.

Parasitic gastroenteritis is frequently linked to poor water sources, explains Merck Manuals. Parasites attach to the lining of the intestines, causing the infection giardiasis and interfering with the body’s ability to absorb nutrients. Accidental exposure to poisonous toxins in plants or food is the most common cause of chemical gastroenteritis, but the condition can be triggered by excessive consumption of acidic foods.

In clinical settings, gastroenteritis is a recurrent symptom of prominent treatments such as chemotherapy, radiation, antacids and antibiotics, states Merck Manuals. However, physicians must weigh the benefits of treatment against the patient's long-term discomfort before deciding to stop using specific drugs or medications.