Nausea and Vomiting

Medically Reviewed on 6/19/2023

What are nausea and vomiting?

Stomach Flu Condition

The major causes of nausea and vomiting include acute gastritis, stomach problems, medications, and mechanical obstruction of the bowel. 

Nausea and vomiting are symptoms of an underlying illness, not a specific disease.

Nausea is the sensation that the stomach wants to empty itself, while vomiting (emesis) is the act of forcible emptying of the stomach. The term "dry heaving" (retching) refers to an episode of vomiting where there is no food in the stomach to vomit, and only small amounts of clear secretions are vomited. Vomiting is a violent act in which the stomach, esophagus, and small intestine forcibly expel contents of the stomach (and sometimes the small intestine) in a coordinated fashion.

What causes nausea and vomiting?

There are many causes of nausea and vomiting, such as the following:

  • Acute gastritis (direct irritation of the stomach lining)
  • Signals from the vomiting center in the brain
  • Other illnesses not due to stomach problems, such as brain tumors, pancreatitis, and appendicitis
  • Medications, medical treatments, illicit or illegal drugs, and drug or alcohol overdose
  • Mechanical obstruction of the bowel

Gastrointestinal (GI) causes of nausea and vomiting

Acute gastritis or esophagitis is often caused by something that irritates the lining of the stomach or throat, for example:

  • Infections: Infections are often the cause of stomach irritation, whether it is a common virus or another type of infection. There may be cramping and upper abdominal pain associated with nausea and vomiting. Fever and chills may be present. Common viral infections include noroviruses and rotavirus. Infection by bacteria in the Helicobacter family (such as H. Pylori) can also be a cause.
  • Stomach flu: Stomach flu (gastroenteritis) is when vomiting and diarrhea occur together and is associated with a viral infection that is outside of the stomach. It should not be confused with the flu (influenza), a viral infection with symptoms that include fever, chills, cough, and muscle pain.
  • Food poisoning: Food poisoning may cause significant vomiting. The most common cause is a toxin released by the bacteria Staphylococcus aureus. Symptoms of food poisoning begin within a couple of hours of eating contaminated or poorly prepared food. Other bacterial causes of food poisoning include Salmonella, Campylobacter, Shigella, E. coli, Listeria, or Clostridium botulinum (botulism).
  • Other stomach irritants: Alcohol, smoking, and nonsteroidal anti-inflammatory medications (NSAIDs) such as aspirin and ibuprofen may irritate the stomach lining and cause nausea and vomiting.
  • Peptic ulcer disease: Peptic ulcer disease symptoms range from mild irritation of the stomach lining to ulcers, which is the formation of a defect in the protective lining of the stomach.
  • Gastroesophageal reflux disease (GERD, reflux esophagitis): Nausea or vomiting is also associated with GERD (acid from the stomach is refluxed into the esophagus).

Pregnancy-related causes of nausea and vomiting (morning sickness)

Vomiting in pregnancy is caused by changes in hormone levels in the bloodstream. Most women experience moderate symptoms of morning sickness, especially during the first trimester. Symptoms of morning sickness during pregnancy usually resolve by the fourth month.

Rarely, a woman may experience severe vomiting, dehydration, and weight loss, which is referred to as hyperemesis gravidarum.


Digestive Disorders: Common Misconceptions See Slideshow

Neurological causes of nausea and vomiting

Neurological causes of nausea and vomiting include the following:

Nausea and vomiting caused by diabetes, diseases, and eating disorders

  • Diabetes: Persons with diabetes may develop nausea because of gastroparesis, a condition in which the stomach fails to empty properly and is likely due to generalized neuropathy (failure of the nerves in the body to send proper signals to and from the brain or regeneration of nerves in the stomach) that is a complication of the disease. People with diabetes can also develop nausea and vomiting if their blood sugars become abnormally high or low (hyperglycemia or hypoglycemia) because the sugar and insulin balance is disturbed.
  • Diseases: Many illnesses associated with the intra-abdominal organs can produce the symptoms of nausea and vomiting. These include digestive organ diseases such as:
  • Abdominal adhesions. Abdominal pain and distention, nausea and vomiting, and inability to pass flatus (gas) or have a bowel movement are symptoms of intestinal (bowel obstruction). Common causes of bowel obstruction include previous surgery with the formation of adhesions, hernias, abnormal twisting of the GI tract, tumors, and inflammatory bowel disease, or IBD (ulcerative colitis and Crohn's disease.
  • Vomiting as an atypical symptom of another disease: Some additional illnesses will cause nausea and vomiting, even though there is no direct involvement of the stomach or gastrointestinal tract.
    • Heart attack victims may experience nausea and vomiting as an atypical symptom of angina, especially if the heart attack affects the inferior or lower part of the heart.
    • Lung infections, for example, pneumonia and bronchitis, may also cause nausea and vomiting, especially if the area of the lung involved is near the diaphragm, the muscle that separates the chest from the abdomen.
  • Sepsis: An overwhelming infection spread through the bloodstream may also be associated with nausea and vomiting.
  • Eating disorders: Patients with bulimia will have self-induced vomiting or purging as part of their psychiatric illness

Nausea and vomiting caused by drug side effects

Nausea and vomiting caused by drug side effects include the following:

  • Side effects from medications: The side effect of many medications include stomach irritation and/or nausea and vomiting. Narcotic pain medications, anti-inflammatory medications, steroids, and antibiotics all have nausea and vomiting listed as common side effects.
  • Radiation therapy: Nausea and vomiting can be associated with radiation therapy.
  • Chemotherapy: Anti-cancer drugs used for chemotherapy commonly cause nausea and vomiting that is not easily relieved.

Vomiting in infants

It may be hard to determine whether an infant is vomiting or spitting up. If the episodes occur shortly after feeding and only a small amount comes up, it may be spitting up.

  • Forceful vomiting: In the first 2-3 months of life, if the vomiting is forceful after eating (imagine it flying across the room), this may be a sign of pyloric stenosis, or an abnormal narrowing of the pylorus, the location where the stomach empties into the duodenum (the first part of the small intestine). The vomiting is described as a projectile. Diagnosis is often made by history and physical examination, confirmed by ultrasound. Treatment is surgery.
  • Vomiting associated with pain: if the infant cries uncontrollably, and if the stool is bloody or red, it may be an intussusception (the pushing of one segment of the bowel into an adjacent segment). The stool is classically described as currant jelly, but any blood in the stool is not normal and should always be a cause for concern. It is reasonable to seek medical care in this case.
  • Viral infection: If there is vomiting with associated diarrhea that is not bloody, a viral infection is a possibility. Alternatively, there may be an issue with intolerance to the type of baby formula. Infants and children are at greater risk of dehydration if the vomiting episodes last for more than 24 hours. If dehydration is suspected, seek medical care. Signs and symptoms of dehydration in an infant include dry mouth, lack of sweat in the armpits and groin, sunken eyes, weak cries, and decreased muscle tone.

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How is the cause of nausea and vomiting diagnosed?

Diagnosis often can be made when the health care professional takes a thorough medical history and performs a physical examination. Any tests that need to be ordered will be based on the information from the history and physical exam, and sometimes no further testing is required to make a diagnosis.

Laboratory tests and X-rays may be ordered to assess the stability of the patient and not necessarily to make a diagnosis. For example, a patient with food poisoning may need blood tests to measure levels of electrolytes (minerals) and other chemicals, since significant amounts of sodium, potassium, and chloride may have been lost from persistent vomiting and diarrhea.

Urinalysis may help assess hydration status. Concentrated, dark urine is associated with dehydration because the kidneys try to preserve as much water as possible in the body. Ketones in the urine are also a sign of dehydration.

What treatments and drugs help relieve nausea or vomiting?

Nausea and vomiting can be treated with medication at the same time as an underlying diagnosis is being made. Ideally, these symptoms should resolve when the underlying illness is treated and controlled.

Nausea and vomiting are often made worse when you are dehydrated, resulting in a vicious cycle. Nausea makes it difficult to keep down fluid, making the dehydration worse, which then increases nausea. Intravenous fluids may be provided to correct this issue and break the cycle.

There are varieties of anti-nausea medications (antiemetics) that your doctor may prescribe. These drugs can be administered in different ways depending upon your ability to take them. Medications are available by pill, liquid, or tablets that dissolve on or under the tongue, by intravenous or intramuscular injection, or by rectal suppository.

Common medications used to control nausea and vomiting include:

The decision as to which medication to use will depend on the patient's condition.

What natural home remedies help relieve nausea and vomiting?

It is important to rest the stomach and avoid dehydration. Clear fluids should be attempted for the first 24 hours, and diet should be advanced as tolerated.

Clear fluids that are easy for the stomach to absorb include:

  • Water
  • Sports drinks
  • Clear broths
  • Popsicles
  • Jell-O

It is important not to take too much fluid at one time since stretching the stomach theoretically may cause nausea to worsen. One to two ounces of fluid at a time, taken every 10-15 minutes, may be all that the stomach will be able to tolerate. In infants and children, the amount may be as little as 5 or 10 cc's or less than a third of an ounce at a time.

Milk products should be avoided for the first 24-48 hours during an episode of nausea and vomiting. If the infection involves the small intestine, the enzyme that helps digest milk located in cells lining the small intestine can become depleted. This can reduce the tolerance to milk and milk-containing products and lead to, bloating, vomiting, and diarrhea. As the affected individual begins to feel better, they can begin to reintroduce foods. However, to help the stomach readjust, healthcare professionals often recommend limiting the diet to bland foods such as bananas, applesauce, rice, and toast (the BRAT diet).

When should I call the doctor for nausea and vomiting?

Medical care should be sought if the following occurs:

  • Symptoms last for more than 24 hours
  • Diagnosis is uncertain
  • There is concern about dehydration,
  • The patient has underlying medical conditions that make them more fragile
  • Nausea and vomiting are associated with 

Infants and children are more susceptible to dehydration and may not have as much reserve as an adult. If there is concern about dehydration or the inability to tolerate fluids, a healthcare professional should be contacted.

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Medically Reviewed on 6/19/2023
Tintinalli J, et al. Tintinalli's Emergency Medicine: A Comprehensive Study Guide. 8th edition. McGraw-Hill Professional 2015.