Key takeaways

Stomach bugs, also known as gastroenteritis, are caused by viruses, bacteria, or parasites, leading to symptoms such as nausea, vomiting, diarrhea, and sometimes fever.
Good hygiene, particularly handwashing, is essential for preventing the spread of stomach bugs.
Treatment for gastroenteritis focuses on symptom relief through hydration, rest, and over-the-counter medications, with prescription medications necessary for bacterial or parasitic infections.
Most cases of viral gastroenteritis resolve within a few days with proper care, but severe or prolonged symptoms require medical attention, especially for individuals with specific health conditions or symptoms like bloody diarrhea.

The prospect of a stomach bug strikes fear in the hearts, minds, and intestines of anyone who has ever spent a long night hunched over the toilet. Stomach bugs tend to hit fast and hit hard. Nausea, vomiting, and diarrhea are the key symptoms. In combination they can make you feel like you’ve been run over by a train.

Unfortunately, you can’t always tell that someone is contagious with something that can make you feel that bad. “The biggest problem is that you’re probably going to get exposed before you realize they have it,” says Steven Furr, MD, a family physician in Jackson, Alabama, and member of the board of directors of the American Academy of Family Physicians (AAFP).

The best way to protect yourself is through good hygiene. So, go wash your hands, then come back and learn more about these dreaded tummy troubles—how long it will probably last, and how to treat the symptoms.

What is a stomach bug?

A stomach bug is an intestinal infection that causes nausea, abdominal pain, vomiting, and diarrhea–and sometimes a fever.

Some people use the phrases “stomach bug,” “stomach virus,” and “stomach flu” interchangeably. The last one is a misnomer. The influenza virus isn’t the culprit for these symptoms. A better term is gastroenteritis.

There are three main causes of gastroenteritis:

Viral: A virus, like norovirus or a rotavirus
Bacterial: Bacteria, like salmonella or E. coli
Parasitic: A parasite, such as giardia or cryptosporidium

In other words, you’re sick because of a pathogen you came into contact with or something you ate. Viral gastroenteritis spreads from person to person, through contaminated surfaces, or when a sick person contaminates food while handling it. Food poisoning can be bacterial (when improperly stored food grows bacteria) or parasitic (when food or water is contaminated with a microorganism or worm). No matter the cause of your illness, all three types make you feel pretty crummy.

How do I know if it’s a stomach bug or something else?

It can be difficult to tell what’s causing your gastrointestinal distress. Different causes have similar symptoms—and when you’re throwing up constantly, you may not really care.

It can be useful to know the culprit, though, because it may affect how you can treat your symptoms. Consider who you’ve been in contact with, what you’ve eaten, and where you’ve been recently, which may give some insight into the potential cause of your illness. Then, consult the following chart.

Compare common stomach viruses
Condition	Cause	Symptoms	Diagnosis	Treatment	Usual Duration
Gastroenteritis	Virus, bacteria, or parasite	Nausea, vomiting, diarrhea, abdominal cramps, dehydration, fever or chills	Physical exam, blood or stool test	Fluids, rest, over-the-counter medication for symptom relief, Rx to treat bacteria or parasite	Depends on the cause: norovirus lasts 2 days, rotavirus lasts 3 to 8 days, campylobacter and salmonella last 2 to 7 days. Overall, expect 24-48 hours before symptoms improve
Influenza (flu)	Influenza virus	Fever, chills, body aches, sore throat, cough, stuffy nose, fatigue	Rapid flu test	Fluids, rest, antiviral medications, such as Tamiflu	5-7 days on average
COVID-19	SARS-CoV-2 virus	Congestion, cough, fever, fatigue, sore throat, loss of smell or taste, nausea, vomiting, diarrhea	COVID-19 test	Fluids, rest, possible hospitalization in severe cases	1-2 weeks for mild cases

How to get rid of a stomach bug

Unless you’re dealing with bacterial or parasitic gastroenteritis, there’s no cure for the condition. Treatment is about alleviating symptoms to help you feel better and start to recover.

1. Fluids

Fluids are critical when it comes to recovering from a bout of gastroenteritis, no matter the cause. “The most important thing in those initial 48 hours is to stay well hydrated,” says David Cutler, MD, a family medicine physician at Providence Saint John’s Health Center in Santa Monica, California. Small frequent sips of clear fluids can help you absorb some of the liquid and avoid getting dehydrated. Consider sucking on popsicles as this gives your body liquids slowly.

Oral rehydration solutions may be superior to sports drinks in maintaining electrolytes in balance while hydrating. Broths are good, too. Be sure to drink what sounds appealing to you, as this may decrease vomiting and increase fluid intake. Avoid soft drinks or sugar containing drinks. Avoid alcohol and drinks containing caffeine, which can make you urinate more, which increases fluid loss.

If you’re having trouble keeping fluids down, “eat ice chips as often as you want or your body will allow,” suggests Jay Woody, MD, chief medical officer of Intuitive Health. You can start taking small sips every 10-15 minutes when you can tolerate beverages.

2. Rest

When your body is recovering from a virus or infection, you need extra sleep. Vomiting, diarrhea, and fever can make you feel extra tired. Listen to your body. Lay down and nap whenever possible.

3. Diet

Patients should eat whatever is tolerated. Smaller meals, broths or soups, and bland, low-residue foods are often better tolerated. While the BRAT diet is suggested as a good way to start introducing food when you’re recovering from gastrointestinal distress, evidence to support this is weak. BRAT stands for Bananas, Rice, Applesauce, and Toast. Essentially, it’s a diet of bland foods that won’t put too much stress on your irritated stomach and intestines.

Just don’t stay on this eating plan after you’ve recovered. It’s low in fiber and protein. The American Academy of Pediatrics (AAP) doesn’t recommend the BRAT diet for infants and young children. Instead, focus on helping your child rehydrate using oral rehydration solutions like Pedialyte.

4. Over-the-counter treatment

Usually, viral gastroenteritis is a self-limited condition that does not need medication. Adequate fluid replacement is the mainstay of treatment. If you’re struggling with diarrhea and vomiting, an over-the-counter medication may help. Two commonly recommended meds are Imodium A-D (loperamide) and Pepto Bismol (bismuth subsalicylate), both of which are anti-diarrheal medications. These are considered safe for adults, but may also mask the amount of fluid loss because fluids may pool in the intestines. The AAP and the World Health Organization recommend not giving loperamide to children.

To alleviate fever or chills, Tylenol (acetaminophen) can help. Avoid ibuprofen, which can irritate an empty stomach, says Dr. Furr.

Some studies show probiotics may decrease the duration of infectious diarrhea, but more research is needed.

5. Prescription medication

For bacterial or parasitic gastroenteritis, you may need an antibiotic or other prescription to recover. An Rx will not help viral infections. If your gastroenteritis is especially severe or bloody or lasts more than two weeks, your healthcare provider may run a stool or blood test to determine the cause of your symptom and order the right medicine.

Patients may need an anti-nausea medication in order to keep fluids down thereby decreasing the need for intravenous fluids and decreasing hospital admission rates.

How long does a stomach bug last?

A typical case of viral gastroenteritis will just last a couple of days (although they will seem like very long days). “Usually in 24 to 48 hours, you’re going to be getting over the symptoms,” Dr. Furr says. “But that first 24 hours can be pretty tough.”

With viral gastroenteritis, time and hydration are key. As miserable as it may seem, you really just have to wait it out. Typically, most mild cases of gastroenteritis will go away on their own within a few days.

With a bacterial or parasitic infection, you might need a course of medication before you start to feel better.

When should you see your healthcare provider?

If someone is in frail health, such as an infant or elderly adult, it’s always a good idea to check in with a healthcare provider. Frail patients may become dehydrated much more quickly, which can lead to a whole host of problems. Patients with the following medical comorbidities require closer follow-up and a lower threshold for hospitalization: immunodeficient, inflammatory bowel disease, diabetes, kidney failure, rheumatoid arthritis, lupus, patients on diuretics.

Alarm signs and symptoms that signal a doctor’s visit is needed, even if you’re otherwise healthy include:

You are urinating less than three times per 24 hours
You have severe abdominal pain
You have had hospitalization or antibiotic use in the past six months
You are pregnant
You experience weight loss
You have blood or pus in the stool
You have bloody vomit
You have diarrhea for more than two weeks

Bloody diarrhea is especially concerning. “That could suggest that something could be more serious,” says Dr. Furr.

After you’ve recovered, you probably want to avoid ever getting sick like that again. For stomach bugs, prevention is key. Dr. Cutler stresses the importance of a behavior that many of us have adopted more stringently since the coronavirus pandemic began: handwashing. “Wash your hands,” he says. “Everyone is in tune with that now, but that is so important.” It might even help you avoid coming down with a stomach virus when another member of your family falls ill with one.