Nausea is an unpleasant feeling of needing to vomit. People also may feel dizziness, vague discomfort in the abdomen, and an unwillingness to eat.
Vomiting is a forceful contraction of the stomach that propels its contents up the esophagus and out the mouth. Vomiting empties the stomach and often makes people with nausea feel considerably better, at least temporarily. Vomiting is quite uncomfortable and can be violent. Severe vomiting can project stomach contents many feet (projectile vomiting). Vomiting is not the same as regurgitation, which is the spitting up of stomach contents without forceful abdominal contractions or nausea. For instance, people with achalasia or Zenker's diverticulum (see Esophageal Disorders: Zenker's Diverticula) may regurgitate undigested food without nausea.
Vomitus—the material that is vomited up—usually reflects what was recently eaten. Sometimes it contains chunks of food. When blood is vomited, the vomitus is usually red (hematemesis—see Symptoms of Digestive Disorders: Gastrointestinal Bleeding), but if the blood has been partly digested, the vomitus looks like coffee grounds. When bile is present, the vomitus is bitter and yellow-green.
In addition to being uncomfortable, vomiting can cause complications:
People who are unconscious or only partly conscious can inhale their vomitus. The acid in the vomitus can severely irritate the lungs.
Vomiting greatly increases pressure within the esophagus, and severe vomiting can tear the lining of the esophagus (see Esophageal Disorders: Esophageal Laceration). A small tear causes pain and sometimes bleeding, but a large tear can be fatal.
Because people lose water and minerals (electrolytes) in vomitus, severe vomiting can cause dehydration and electrolyte abnormalities. Newborns and infants are particularly susceptible to these complications.
Chronic vomiting can cause undernutrition, weight loss, and metabolic abnormalities.
Nausea and vomiting result when the vomiting center in the brain is activated. Causes typically involve disorders of the digestive tract or the brain, or ingested substances.
The most common causes of nausea and vomiting are
Nausea and vomiting commonly occur with any dysfunction of the digestive tract but are particularly common with gastroenteritis (see Gastroenteritis). A less common digestive tract disorder is intestinal obstruction (obstruction of the intestine), which causes vomiting because food and fluids back up into the stomach because of the obstruction. Many other abdominal disorders that cause vomiting also cause significant abdominal pain (see Symptoms of Digestive Disorders: Acute Abdominal Pain). In such disorders (for example, appendicitis or pancreatitis), it is typically the pain rather than the vomiting that causes people to seek medical care.
Many drugs, including alcohol, opioid analgesics (such as morphine), and chemotherapy drugs, can cause nausea and vomiting. Toxins, such as lead or those found in some foods and plants, can cause severe nausea and vomiting.
Less common causes:
Less common causes of nausea and vomiting include
The vomiting center also can be activated by certain brain or central nervous system disorders, including infections (such as meningitis and encephalitis), migraines, and disorders that increase pressure inside the skull (intracranial pressure). Disorders that increase intracranial pressure include brain tumors, brain hemorrhage, and severe head injuries.
The balance organs of the inner ear (vestibular apparatus) are connected to the vomiting center. This connection is why some people become nauseated by the movement of a boat, car, or airplane and by certain disorders of the inner ear (such as labyrinthitis and positional vertigo).
Nausea and vomiting may also occur when there are metabolic changes in the body, such as during early pregnancy, or when people have diabetes that is severely out of control, or severe liver failure or kidney failure.
Psychologic problems also can cause nausea and vomiting (known as functional, or psychogenic, vomiting). Such vomiting may be intentional. For instance, people who have bulimia make themselves vomit to lose weight. Or it may be unintentional. For instance, children who are afraid of going to school vomit as a response to their psychologic distress.
Not every episode of nausea and vomiting requires immediate evaluation by a doctor. The following information can help people decide whether a doctor's evaluation is needed and help them know what to expect during the evaluation.
Certain symptoms and characteristics are cause for concern. They include
When to see a doctor:
People who have warning signs should see a doctor right away, as should people who vomited any blood or who recently had a head injury.
People who have nausea and vomiting but no warning signs should see a doctor if vomiting continues for more than 24 to 48 hours or if they are unable to tolerate more than a few sips of liquid. People who have a few episodes of vomiting (with or without diarrhea) but are able to tolerate at least some liquids should call their doctor. Depending on their age, other symptoms, and known medical conditions (such as cancer or diabetes), the doctor may suggest people are seen for an evaluation or stay home and try simple remedies.
What the doctor does:
Doctors first ask questions about the person's symptoms and medical history. Doctors then do a physical examination. What they find during the history and physical examination often suggests a cause of the vomiting and the tests that may need to be done (see see Symptoms of Digestive Disorders: Some Causes and Features of Nausea and Vomiting).
During the history, doctors ask whether the person is pregnant or has diabetes, migraines, liver or kidney disease, or cancer (including the timing of any chemotherapy or radiation therapy). All recently ingested drugs and substances are noted because certain substances may not be toxic until several days after ingestion (such as acetaminophen and some mushrooms).
During the physical examination, doctors look for the following:
Doctors note any previous abdominal surgery, because fibrous bands of scar tissue (adhesions) may have formed and caused a intestinal obstruction.
Although people with previously known disorders that cause vomiting (such as migraine) may simply be having a recurrence of that disorder, doctors thoroughly look for signs of a new, different problem.
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The need for tests depends on what doctors find during the history and physical examination, particularly whether warning signs are present and whether findings suggest a particular disorder (see Symptoms of Digestive Disorders: Some Causes and Features of Nausea and Vomiting).
Possible tests include
Girls and women of childbearing age typically should have a pregnancy test.
Otherwise healthy adults and older children who have only a few episodes of vomiting (with or without diarrhea) and no other symptoms typically do not require any testing.
People whose vomiting is severe or has lasted more than 1 day or who have signs of dehydration need laboratory tests of blood (particularly electrolyte levels and sometimes liver tests) and urine.
Specific conditions are treated. If there is no serious underlying disorder and the person is not dehydrated, small amounts of clear liquids may be given 30 minutes or so after the last bout of vomiting. Typically an ounce (30 milliliters) or two are given at first. Plain water is an appropriate liquid, but broth or weak, sweetened tea may be given. Sports drinks have no particular advantage but are not harmful. Carbonated beverages and alcohol should be avoided. If these liquids are tolerated, the amounts are increased gradually. When these increases are tolerated, the person may resume eating normal foods.
Even when people are slightly dehydrated, doctors usually recommend oral rehydration solutions as long as people can tolerate some liquids by mouth. People with significant dehydration or electrolyte abnormalities, people who are actively vomiting, and people who cannot tolerate any liquids by mouth usually require fluids and/or drugs given by vein (intravenously).
For some adults and adolescents, doctors give anti-nausea drugs depending on the cause and the severity of the vomiting:
Last full review/revision October 2012 by Norton J. Greenberger, MD