Health Conditions A-Z Digestive Disorders Signs and Symptoms of Stomach Flu Medically known as viral gastroenteritis, the so-called stomach flu can cause nausea, vomiting, diarrhea, and other unpleasant symptoms. By Amanda Gardner Updated on May 17, 2023 Medically reviewed by Jay N. Yepuri, MD Medically reviewed by Jay N. Yepuri, MD Jay N. Yepuri, MD, MS, FACG, is a board-certified gastroenterologist and member of the Digestive Health Associates of Texas Board of Directors and Executive Committee. learn more Share this page on Facebook Share this page on Twitter Share this page on Pinterest Email this page Stomach flu, or viral gastroenteritis, is a condition where your stomach lining is inflamed. However, stomach flu symptoms are not similar to those of the actual flu. Symptoms like nausea, vomiting, and diarrhea are more likely the result of a gastrointestinal virus. True influenza only affects your airways. Anyone can experience symptoms of the flu. Symptoms of the stomach flu usually show up one to three days after you're infected. Some cases are mild, lasting 24 or 48 hours. Cases usually last less than a week. How Do You Get the Stomach Flu? Watery Diarrhea Watery diarrhea refers to really loose and watery bowel movements. This type of diarrhea happens because the infection prevents your large intestine from retaining fluid. Instead, it leaves your body in the form of loose, watery stools. Blood or mucus in your stool rarely occurs with the stomach flu; they are signs you should head to the emergency room. Nausea and Vomiting Nausea and vomiting are common symptoms of gastroenteritis. While certainly unpleasant, these symptoms are actually a good sign: Your body is trying to get rid of the bad stuff. Nausea helps protect you from ingesting toxic substances further, while vomiting is a way of removing them from your body. Abdominal Pain Abdominal cramps or abdominal pain are also common. This is the discomfort felt in between a person's chest and grown. The cramps or pain may feel like generalized pain—which spans over half of a person's belly—typical for stomach viruses. Low-Grade Fever Fevers refer to short-term body temperature increases due to diseases or illnesses. Low-grade fevers can be a stomach flu symptom—about 50% of individuals will have a fever. This is usually nothing to worry about, but a higher one might be. A temperature above 102°F may be a sign that dehydration is becoming severe. Dehydration Dehydration happens when a person doesn't get enough fluid to replace any lost. This condition is a complication of the stomach flu. It's a symptom that needs to be addressed since it can cause your condition to get even worse. If you're dehydrated, you may: Feel dizzy, lightheaded, or confused Feel tired Feel very thirsty Have a dry mouth Less bounce of the skin when pressed Sunken eyes or cheeks Urinate infrequently and notice dark, yellow urine Beyond the above symptoms, other specific dehydration signs in younger children include no wet diapers for three or more hours and tear-free crying. Symptoms in Children Gastroenteritis happens most often in children younger than 5 years old. Many stomach flu symptoms for infants and children are the same as those for adults. Children may also experience a low appetite, and mild vomiting may follow the onset of diarrhea. When To See a Healthcare Provider Though gastrointestinal viruses usually resolve with good self-care, there are some signs that you need urgent medical care. Go to an emergency room if you have any of these symptoms: Black or tarry stools or stools containing blood or pusDehydrationDiarrhea for more than one dayAny fever in infants or high fever in older children and adultsFrequent loose stoolsFrequent vomitingMental state changesSevere abdomen or rectum pain Infants and children will also need immediate medical care if they have any of the above symptoms, especially if they have signs of dehydration. Untreated dehydration in children can be fatal within a day. Is It Food Poisoning–or the Stomach Flu? Here's How to Tell A Quick Review Stomach flu symptoms include watery diarrhea, nausea, vomiting, abdominal pain, and sometimes a low-grade fever. Babies and children with the stomach flu may have these symptoms, along with a lack of appetite. Though the stomach flu may go away after a few days, it's important to watch for signs of dehydration that come with the illness. Dehydration and symptoms such as mental status changes and severe stomach pain require immediate medical care if you have the stomach flu. Was this page helpful? Thanks for your feedback! Tell us why! Other Submit 14 Sources Health.com uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. American Academy of Family Physicians. Stomach flu (gastroenteritis). Centers for Disease Control and Prevention. Norovirus - symptoms. MedlinePlus. Diarrhea. Merck Manual Professional Version. Diarrhea. MedlinePlus. Nausea and vomiting. Singh P, Yoon SS, Kuo B. Nausea: a review of pathophysiology and therapeutics. Therap Adv Gastroenterol. 2016;9(1):98-112. doi:10.1177/1756283X15618131 Zhong W, Shahbaz O, Teskey G, et al. Mechanisms of nausea and vomiting: current knowledge and recent advances in intracellular emetic signaling systems. IJMS. 2021;22(11):5797. doi:10.3390/ijms22115797 MedlinePlus. Abdominal pain. MedlinePlus. Fever. Merck Manual Professional Version. Overview of gastroenteritis. MedlinePlus. Dehydration. National Institute of Diabetes and Digestive and Kidney Diseases. Symptoms & causes of viral gastroenteritis ("stomach flu"). Rivera-Dominguez G, Ward R. Pediatric gastroenteritis. In: StatPearls. StatPearls Publishing; 2023. Merck Manual Consumer Version. Gastroenteritis in children.