The stomach flu is a common condition, especially affecting those who spend time in shared spaces. The medical term for the stomach flu is viral gastroenteritis, and symptoms come from inflammation and irritation of the small intestine. Infection occurs through contact with other infected patients, contaminated objects such as doorknobs and smooth surfaces, and by ingesting contaminated food and water. As the body fights the infection, people develop a range of signs and symptoms.


Many people with gastroenteritis report fatigue or a general lack of energy. What makes fatigue especially debilitating is the fact that it does not each with rest; it can persist until the condition resolves. This symptom occurs because the body is using a lot of energy to fight the infection. This preoccupation with recovery also means nutrients in food are not properly absorbed. Although many things may cause fatigue, if other symptoms point to gastroenteritis, a stomach infection is the likely culprit. If fatigue does not improve after 48 hours, it is best to speak to a doctor.



Some people with gastroenteritis develop a fever, one of the body's most effective ways of eradicating an infection. Though a fever can be a sign that the body is doing its job, if temperatures of above 102 degrees Fahrenheit persist for more than four days, medical attention is required. Fever can also lead to chills.



As a result of gastroenteritis, some people develop symptoms not directly related to the stomach, including headaches. This seemingly unrelated symptom develops due to chemical imbalances in the brain caused by the virus. Luckily, an affected individual can usually ease headaches with over-the-counter pain medications, rest, and drinking plenty of fluids. The latter is a vital step toward fighting off the infection, in general.


Sore Muscles

Experiencing some degree of pain or soreness in the muscles is one of the most common symptoms of gastroenteritis. Also known as myalgia, a variety of viral infections can cause this symptom. Myalgia can affect different muscles or muscle groups, and the damage incurred by the muscle fibers can make it painful or difficult to move the arms or legs and carry out general daily activities.


Abdominal Pain

Abdominal pain is a common and understandable symptom of gastroenteritis. The muscles in the wall of the small intestine contract in an effort to expel the infection, which leads to pain in this region. Anti-diarrheal medications can help alleviate this symptom if an infection is not the cause, but should be avoided if other signs such as vomiting or fever are also present. In the latter case, taking medications that prevent vomiting or diarrhea can prolong the illness, as these actions are how the body rids itself of the virus.


Nausea and Vomiting

Vomiting and nausea go hand in hand and are amongst the strongest indications of a stomach-related condition. Vomiting, like fever, is a natural reaction to the presence of an infection. By forcefully expelling unwanted substances from the stomach, the body fights the condition. Nausea is the feeling that you may vomit and is caused by the brain as a signal to the stomach.



Diarrhea can be a dangerous sign of gastroenteritis because it can lead to dehydration, which removes important ions like sodium and chloride the body requires to function efficiently. Drinking water and electrolyte-containing fluids is essential to replenish those that are lost. 


Bloody Stool

Experiencing blood in the stool might sound frightening, but it is not always a sign of something perilous; in many cases, it is simply a warning sign that warrants further attention. A person who notices black or blood-streaked bowel movements should contact a doctor. The darker the blood, the more internal the issue: light red blood indicates bleeding around the anus, while dark blood indicates blood that has traveled from the colon or small intestine.



As noted, dehydration occurs when the body is depleted of fluids and the essential nutrients they provide. In the case of gastroenteritis, this symptom stems from the excessive elimination of fluids through diarrhea and vomiting. Signs of dehydration include dizziness, red eyes, dry skin, and fatigue. It is always important to consume enough fluids throughout the day and is even more vital as the body fights a viral infection.


Decreased Urination

As the body becomes low on fluids, it is normal to experience less urination. This is yet another reason to drink a lot of water and other healthy liquids when experiencing gastroenteritis. The kidneys need copious amounts of water to process and clean the blood efficiently. A lack of water can lead to kidney failure.


Loss of Appetite

Many people who experience gastroenteritis notice a significant decrease in their appetites. This symptom isn't just about food aversion — it's about how the body's response to infection can make the thought of eating unappealing. Since the stomach and intestines are inflamed and irritated, these organs send signals to the brain that suppress hunger cues, making it challenging to maintain normal eating habits. For that reason, it's essential to eat small, light meals to aid recovery and keep hydration levels up when you're suffering from this illness.

African-American man having no appetite, eating disorder, depression problem


Mucus in the Stools

A less talked about but equally important symptom of gastroenteritis is the appearance of mucus in stools. This jelly-like substance helps lubricate the intestines, but when present in excessive amounts in bowel movements, mucus may indicate inflammation or infection. Part of the body's response to fighting off the gastroenteritis-causing pathogens, mucus in the stool typically appears when the body is actively trying to rid itself of the illness, though it might be alarming to see.

Mucus in human stool.


Frequent Urges to Defecate

Gastroenteritis can lead to an increased urgency to defecate, often with little warning. This symptom occurs due to irritation and inflammation in the digestive tract, stimulating the bowels and making you feel like you need to use the bathroom more frequently. Even if you only expel a small amount of feces, the sensation of needing to go may persist and cause discomfort. Frequent bowel movements can lead to dehydration, making it crucial to drink lots of water when you're suffering from gastroenteritis.

Elderly men who have trouble with excretion


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