Diarrhea

Diarrhea — loose, watery and possibly more-frequent bowel movements — is a common problem. Sometimes, it's the only symptom. At other times, it may be associated with other symptoms, such as nausea, vomiting, abdominal pain or weight loss.

Luckily, diarrhea is usually short-lived, lasting no more than a few days. But when diarrhea lasts beyond a few days into weeks, it usually means that there's another problem — such as irritable bowel syndrome (IBS) or a more serious disorder, including ongoing infection, celiac disease or inflammatory bowel disease (IBD).

Colon and small intestine

The small intestine and colon are components of your digestive tract, which processes the foods you eat. The intestines extract nutrients from the foods. What isn't absorbed by the intestines continues along the digestive tract and is expelled as stool during a bowel movement. Diarrhea can be present due to irregularities in the small intestine or the large intestine.

Symptoms associated with diarrhea (loose, watery stools) may include:

• Belly cramps or pain.
• Bloating.
• Nausea.
• Vomiting.
• Fever.
• Blood in the stool.
• Mucus in the stool.
• Urgent need to have a bowel movement.

A number of diseases and conditions can cause diarrhea, including:

• Viruses. Viruses that can cause diarrhea include Norwalk virus (also known as norovirus), enteric adenoviruses, astrovirus, cytomegalovirus and viral hepatitis. Rotavirus is a common cause of acute childhood diarrhea. The virus that causes coronavirus disease 2019 (COVID-19) also has been associated with gastrointestinal symptoms, including nausea, vomiting and diarrhea.
• Bacteria and parasites. Exposure to certain bacteria, such as E. coli or parasites through contaminated food or water, leads to diarrhea. A parasite called cyclospora can cause an intestinal illness called cyclosporiasis. In the United States, outbreaks of cyclosporiasis have been linked to fresh produce. Reports of illness often rise in the spring and summer. When traveling in developing countries, diarrhea caused by bacteria and parasites is often called traveler's diarrhea. Clostridioides difficile (also known as C. diff) is another type of bacterium that causes diarrhea, and it can occur after a course of antibiotics or during a hospitalization.
• Medicines. Many medicines, such as antibiotics, can cause diarrhea. Antibiotics get rid of infections by killing bad bacteria, but they also kill good bacteria. This disturbs the natural balance of bacteria in your intestines, leading to diarrhea or an infection such as C. diff. Other drugs that cause diarrhea are anti-cancer drugs and antacids with magnesium.
• Lactose intolerance. Lactose is a sugar found in milk and other dairy products. People who have trouble digesting lactose have diarrhea after eating dairy products. Lactose intolerance can increase with age because levels of the enzyme that helps digest lactose drop as you get older.
• Fructose. Fructose is a sugar found naturally in fruits and honey. It's sometimes added as a sweetener to certain beverages. Fructose can lead to diarrhea in people who have trouble digesting it.
• Artificial sweeteners. Sorbitol, erythritol and mannitol — artificial sweeteners are nonabsorbable sugars found in chewing gum and other sugar-free products — can cause diarrhea in some otherwise healthy people.
• Surgery. Partial intestine or gallbladder removal surgeries can sometimes cause diarrhea.
• Other digestive disorders. Chronic diarrhea has a number of other causes, such as IBS, Crohn's disease, ulcerative colitis, celiac disease, microscopic colitis and small intestinal bacterial overgrowth (SIBO).

Diarrhea can cause dehydration, which can be life-threatening if untreated. Dehydration is particularly dangerous in children, older adults and those with weakened immune systems.

If you have signs of serious dehydration, seek medical help.