Vomiting and diarrhea can happen at the same time for a number of reasons.

A stomach virus or bacterial gastrointestinal (GI) infection is the most likely cause in children.

These infections can affect adults as well. But there are a number of other reasons why an adult may experience these symptoms simultaneously, such as drinking too much alcohol or being pregnant.

1. Viral gastroenteritis

Viral gastroenteritis is an intestinal infection. Viral gastroenteritis is often referred to as the stomach flu, but it’s unrelated to influenza (the flu) and is caused by different viruses.

The viruses that most commonly cause gastroenteritis include:

• norovirus
• rotavirus
• adenovirus
• astrovirus

While all of these viruses can affect people of any age, the latter three are most common in infants and toddlers, according to the National Institute of Diabetes and Digestive and Kidney Diseases .

These viruses are transmitted from person to person by contact with infected stool and vomit. This can happen when a person with the infection doesn’t wash their hands thoroughly after using the restroom and then touches surfaces used by other people or prepares food for others.

In addition to vomiting and watery diarrhea , symptoms of viral gastroenteritis include:

• abdominal pain and cramping
• nausea
• fever , on occasion

There are several types of irritable bowel syndrome (IBS) .

One type is known as post-infectious irritable bowel syndrome (PI-IBS). PI-IBS is caused by an infection (usually gastroenteritis).

One large survey , published in 2018, asked thousands of people with IBS about their experiences. Data was collected between 2008 and 2015. Respondents came from countries around the world, with almost half of them being Italian.

The researchers found that infection may have caused IBS in 13.3 percent of respondents. According to the researchers, this statistic was in line with previous surveys, where PI-IBS was reported to comprise 6 to 17 percent of IBS cases.

2. Food poisoning

Food poisoning is an infection of the GI tract. It’s most often caused by bacteria but can also be caused by parasites or viruses.

You can get food poisoning by eating contaminated food. This can happen at home or in restaurants when food is handled incorrectly or not cooked properly.

Several bacteria can cause food poisoning, including:

• E. coli
• Campylobacter
• Listeria monocytogenes
• Salmonella
• Shigella
• Staphylococcus aureus

Symptoms of food poisoning can start within hours of eating contaminated food and often resolve within a few hours to a few days. This usually happens without special treatment.

Vomiting and watery diarrhea are the most common symptoms. Other symptoms include:

• abdominal pain and cramping
• nausea
• fever
• bloody diarrhea

3. Traveler’s diarrhea

Traveler’s diarrhea is a digestive tract disorder that’s most often caused by viruses, parasites, or bacteria consumed in water or food. It’s most likely to occur when you’re visiting an area with a different climate or sanitation practices than what you’re accustomed to at home.

To see if there’s a health notice for the regions to which you’ve recently traveled, check the website of the Centers for Disease Control and Prevention (CDC) .

Traveler’s diarrhea generally clears up within 1 week . Watery diarrhea and cramps are the most common symptoms, but traveler’s diarrhea can also cause:

• nausea
• fever
• flatulence (gas)
• bloating
• tenesmus , or the urgent need to have a bowel movement

4. Stress or anxiety

Research shows that gastrointestinal function is influenced by stress, and that stress and anxiety commonly cause a number of gastrointestinal symptoms, including:

• nausea
• constipation
• indigestion
• heartburn

The stress hormones released by your body slow motility, or movement, in your stomach and small intestine. They also trigger an increase in motility in your large intestine.

Stress and anxiety have also been linked to the development and worsening of irritable bowel syndrome (IBS) as well as inflammatory bowel disease (IBD) .

5. Pregnancy

The body goes through numerous changes during pregnancy.

Morning sickness is the most common cause of vomiting in pregnancy. Despite its name, morning sickness can occur at any time of the day . It affects almost 75 percent of pregnant women, usually during the first 14 weeks of pregnancy.

Some people develop hyperemesis gravidarum , a condition that causes severe nausea and vomiting.

Vomiting and diarrhea in pregnancy can be caused by hormonal changes , new food sensitivities , and dietary changes. Prenatal vitamins also cause diarrhea in some people.

These symptoms can also be caused by gastroenteritis, which is common during pregnancy.

6. Overeating or overdrinking

Overindulging in food or drink can cause vomiting and diarrhea along with:

• indigestion
• heartburn
• belching
• a feeling of uncomfortable fullness

The type of food you eat also matters. Eating large amounts of greasy or sugary foods can irritate your stomach and cause vomiting and diarrhea.

Overeating is even more likely to cause these symptoms if you already have a gastrointestinal condition, such as IBS, stomach ulcers , acid reflux , or gastroesophageal reflux disease (GERD).

The relationship between alcohol and the gut is complex. Some types of alcohol, including sugary drinks, can cause diarrhea by inducing a quicker gut transit time. This decreases digestion, as the gut doesn’t have time to absorb the nutrients or other substances that are rapidly passing through it.

Excessive alcohol use can cause a condition known as alcoholic gastritis, which is an irritation of the stomach lining. Acute gastritis can occur after binge drinking, or gastritis can become chronic in people who drink alcohol regularly.

Gastritis can cause:

• upper abdominal pain or burning
• nausea
• bloating
• regurgitation
• symptoms that improve or worsen after eating, depending on the food

7. Medications

Vomiting and diarrhea are side effects of many medications. Some are more likely to cause these symptoms than others. This can be because of the way the medication works or because they contain additives that irritate the stomach.

Your age, overall health, and other medications can also increase the risk of side effects.

Medications that commonly cause vomiting and diarrhea include:

• certain antibiotics
• nonsteroidal anti-inflammatory drugs (NSAIDS) , such as ibuprofen (Advil, Motrin) and aspirin
• chemotherapy drugs
• metformin (Fortamet, Glumetza)

One way antibiotics can cause vomiting and diarrhea is by killing the “good” bacteria that normally lives in your GI tract. This allows bacteria called Clostridioides difficile to become overgrown, which can result in symptoms similar to severe food poisoning.

Taking medication with food can sometimes relieve symptoms. Speak with a doctor about the best way to take your medication.

Vomiting and diarrhea that occur without a fever can be caused by:

• stress and anxiety
• pregnancy
• medications
• consuming too much food or alcohol

Mild cases of viral gastroenteritis can also cause vomiting and diarrhea without fever.

Dehydration is a complication of vomiting and diarrhea, and it occurs when the body loses too much fluid. Dehydration can prevent your cells, tissues, and organs from functioning properly, leading to serious complications, including shock and even death.

Mild dehydration can be treated at home, but severe dehydration requires emergency care in a hospital.

Symptoms of dehydration in babies , toddlers, and children include:

• thirst
• urinating less than usual, or going 3 or more hours without a wet diaper
• dry mouth
• sunken eyes or cheeks
• decreased skin turgor , or elasticity
• lack of energy
• no tears when crying

Symptoms in adults include:

• extreme thirst
• urinating less than usual
• dry mouth
• sunken eyes or cheeks
• decreased skin turgor
• fatigue
• lightheadedness
• dark-colored urine

Most of the time, vomiting and diarrhea will resolve within a few days without treatment. Home remedies and medications can help you manage your symptoms and avoid dehydration.

Home remedies

Here are some ways you can treat vomiting and diarrhea at home to avoid dehydration:

• Get plenty of rest.
• Avoid stress.
• Wash your hands with soap and water frequently.
• Drink lots of clear fluids like water, broth, clear sodas, and sports drinks.
• Eat saltine crackers.
• Follow the BRAT diet , which consists of bland foods. BRAT stands for bananas, rice, applesauce, and toast.
• Avoid foods that are greasy, spicy, or high in fat and sugar.
• Avoid dairy.
• Avoid caffeine.

Follow this advice if you have babies or toddlers:

• Give your baby smaller feedings more often if needed.
• Give sips of water between formula or solid food.
• Give them an oral rehydration solution, such as Pedialyte .

Medications

There are over-the-counter (OTC) and prescription medications available for vomiting and diarrhea. While generally safe for adults, OTC medications should not be taken without first consulting a doctor.

OTC medications include:

• bismuth subsalicylate ( Pepto-Bismol , Kaopectate)
• loperamide ( Imodium )
• antiemetic drugs , such as Dramamine and Gravol, which often contain the ingredient dimenhydrinate

A doctor may recommend antibiotics to treat vomiting and diarrhea caused by bacterial infections, such as food poisoning.

When you’re experiencing vomiting and diarrhea, your aim should be to get some sustenance and avoid dehydration.

If an infection like gastroenteritis is causing your symptoms, start by trying home remedies. In other cases, professional medical care may be required.

For children

Take a child to the doctor if they:

• are vomiting for more than 2 days or have diarrhea for more than 7 days
• are unable to keep fluid down
• are under 3 months old with a rectal temperature of 100.4°F (38°C)
• are 3 months to 3 years old with a temperature of 102.2°F (39°C)
• are under 5 years old and appear to have symptoms of dehydration, such as:
  • dry mucous membranes
  • drowsiness
  • irritability that doesn’t go away when they’re consoled

It’s especially important to contact a doctor about possible dehydration if the child is too young to describe their own symptoms.

For adults

See a doctor if:

• you’re still dehydrated after rehydrating with fluids and an oral hydration solution
• you are vomiting for more than 2 days or have diarrhea for more than 7 days
• your vomit is green or yellow , which can be a symptom of small bowel obstruction
• you’re vomiting blood or what looks like coffee grounds
• you have bloody diarrhea or rectal bleeding
• you’re unable to keep fluid down

Most of the time, vomiting and diarrhea are due to a stomach bug or food poisoning and clear up on their own within a few days. Getting plenty of fluids and eating a bland diet can help.

Keep an eye out for signs of dehydration, especially in infants and toddlers who are not able to communicate what they’re feeling. Talk with a doctor if you have, or your child has, severe symptoms or symptoms that last more than a few days.