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. (See also Vomiting in Infants and Children Vomiting in Infants and Children Vomiting is the uncomfortable, involuntary, forceful throwing up of food. In infants, vomiting must be distinguished from spitting up. Infants often spit up small amounts while being fed or... read more .) 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 Regurgitation and Rumination Regurgitation is the spitting up of food from the esophagus or stomach without nausea or forceful contractions of the abdominal muscles. Rumination is regurgitation with no apparent physical... read more , which is the spitting up of stomach contents without forceful abdominal contractions or nausea. For instance, people with achalasia Achalasia Achalasia is a disorder in which the rhythmic contractions of the esophagus (called peristalsis) are missing or impaired, the lower esophageal sphincter does not relax normally, and the resting... read more or Zenker diverticulum Zenker diverticula (pharyngeal diverticula) Esophageal diverticula are abnormal pouches or pockets in the esophagus. Rarely, they cause swallowing difficulties and regurgitation (the spitting up of food without nausea or forceful contractions... read more 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 Gastrointestinal Bleeding Bleeding may occur anywhere along the digestive (gastrointestinal [GI]) tract, from the mouth to the anus. Blood may be easily seen by the naked eye (overt), or blood may be present in amounts... read more ), 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:
Inhaled vomitus (aspiration)
Torn esophagus (Mallory-Weiss tear Esophageal Laceration (Mallory-Weiss Syndrome) An esophageal laceration (Mallory-Weiss syndrome) is a tear that does not penetrate the wall of the esophagus. The tear can be caused by forceful vomiting. Symptoms include blood in vomit. The... read more , Boerhaave syndrome Esophageal Ruptures Esophageal ruptures are tears that penetrate the wall of the esophagus. Ruptures can be caused by surgical procedures, severe vomiting, or swallowing a large piece of food that becomes stuck... read more )
Dehydration and electrolyte abnormalities
Undernutrition and weight loss
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 Injury to the Esophagus Esophageal Laceration (Mallory-Weiss Syndrome) An esophageal laceration (Mallory-Weiss syndrome) is a tear that does not penetrate the wall of the esophagus. The tear can be caused by forceful vomiting. Symptoms include blood in vomit. The... read more ). 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 Dehydration Dehydration is a deficiency of water in the body. Vomiting, diarrhea, excessive sweating, burns, kidney failure, and use of diuretics may cause dehydration. People feel thirsty, and as dehydration... read more and electrolyte abnormalities Overview of Electrolytes Well over half of the body's weight is made up of water. Doctors think about the body's water as being restricted to various spaces, called fluid compartments. The three main compartments are... read more . Newborns and infants are particularly susceptible to these complications.
Chronic vomiting can cause undernutrition Undernutrition Undernutrition is a deficiency of calories or of one or more essential nutrients. Undernutrition may develop because people cannot obtain or prepare food, have a disorder that makes eating or... read more , weight loss, and metabolic abnormalities.
Causes of Nausea and Vomiting
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
Gastroenteritis (infection of the digestive tract)
Nausea and vomiting commonly occur with any dysfunction of the digestive tract but are particularly common with gastroenteritis Gastroenteritis . A less common digestive tract disorder is obstruction of the intestine Intestinal Obstruction An obstruction of the intestine is a blockage that completely stops or seriously impairs the passage of food, fluid, digestive secretions, and gas through the intestines. The most common causes... read more , 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 Acute Abdominal Pain Abdominal pain is common and often minor. Severe abdominal pain that comes on quickly, however, almost always indicates a significant problem. The pain may be the only sign of the need for surgery... read more . In such disorders (for example, appendicitis Appendicitis Appendicitis is inflammation and infection of the appendix. Often a blockage inside the appendix causes the appendix to become inflamed and infected. Abdominal pain, nausea, and fever are common... read more or pancreatitis Overview of Pancreatitis Pancreatitis is inflammation of the pancreas. The pancreas is a leaf-shaped organ about 5 inches (about 13 centimeters) long. It is surrounded by the lower edge of the stomach and the first... read more ), 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), cannabis (marijuana), 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
Brain or central nervous system disorders
Metabolic changes or bodywide (systemic) illness
Cyclic vomiting syndrome
The vomiting center also can be activated by certain brain or central nervous system disorders, including infections (such as meningitis Introduction to Meningitis Meningitis is inflammation of the layers of tissue that cover the brain and spinal cord (meninges) and of the fluid-filled space between the meninges (subarachnoid space). Meningitis can be... read more and encephalitis Encephalitis Encephalitis is inflammation of the brain that occurs when a virus directly infects the brain or when a virus, vaccine, or something else triggers inflammation. The spinal cord may also be involved... read more ), migraines Migraines A migraine headache is typically a pulsating or throbbing pain that ranges from moderate to severe. It can affect one or both sides of the head. It is often worsened by physical activity, light... read more , and disorders that increase pressure inside the skull (intracranial pressure). Disorders that increase intracranial pressure include brain tumors Overview of Brain Tumors A brain tumor can be a noncancerous (benign) or cancerous (malignant) growth in the brain. It may originate in the brain or have spread (metastasized) to the brain from another part of the body... read more , brain hemorrhage Intracerebral Hemorrhage An intracerebral hemorrhage is bleeding within the brain. Intracerebral hemorrhage usually results from chronic high blood pressure. The first symptom is often a severe headache. Diagnosis is... read more , and severe head injuries Overview of Head Injuries Head injuries that involve the brain are particularly concerning. Common causes of head injuries include falls, motor vehicle crashes, assaults, and mishaps during sports and recreational activities... read more .
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 Purulent Labyrinthitis Purulent (suppurative) labyrinthitis is a bacterial infection of the inner ear that often causes deafness and loss of balance. The labyrinth is the bony cavity that contains the inner ear. The... read more and positional vertigo Benign Paroxysmal Positional Vertigo Benign paroxysmal positional vertigo, or BPPV, is a common disorder causing short episodes of vertigo (a false sensation of moving or spinning) in response to changes in head position that stimulate... read more ).
Nausea and vomiting may also occur when there are metabolic changes in the body, such as during early pregnancy, or when people have diabetes Diabetes Mellitus (DM) Diabetes mellitus is a disorder in which the body does not produce enough or respond normally to insulin, causing blood sugar (glucose) levels to be abnormally high. Urination and thirst are... read more that is severely out of control or severe liver failure Liver Failure Liver failure is severe deterioration in liver function. Liver failure is caused by a disorder or substance that damages the liver. Most people have jaundice (yellow skin and eyes), feel tired... read more or kidney failure Overview of Kidney Failure This chapter includes a new section on COVID-19 and acute kidney injury (AKI). Kidney failure is the inability of the kidneys to adequately filter metabolic waste products from the blood. Kidney... read more .
Chronic nausea and vomiting syndrome is a functional disorder. That is, the nausea and vomiting are not caused by a physical or specific psychologic disorder but rather may be a problem with the way the brain and gastrointestinal system communicate. In this syndrome, people have bothersome nausea, vomiting, or both that occur at least once a week for at least 6 months including the last 3 months and that have no identifiable cause after testing has been done.
Psychologic problems also can cause nausea and 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.
Cyclic vomiting syndrome is an uncommon disorder in which people have severe attacks of vomiting (or sometimes only nausea) at varying intervals. People feel normal between attacks. Although it usually starts in childhood, it sometimes lasts until adulthood. Cyclic vomiting that begins in adulthood is often due to chronic marijuana use. The vomiting can be relieved by a hot bath and goes away after people stop using marijuana.
Evaluation of Nausea and Vomiting
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
Signs of dehydration Dehydration Dehydration is a deficiency of water in the body. Vomiting, diarrhea, excessive sweating, burns, kidney failure, and use of diuretics may cause dehydration. People feel thirsty, and as dehydration... read more (such as thirst, dry mouth, little or no urine output, and feeling weak and tired)
Headache, stiff neck, confusion, or decreased alertness
Constant abdominal pain
Tenderness when the abdomen is touched
Distended (swollen) abdomen
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 that people be 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 Table: Some Causes and Features of Nausea and Vomiting 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:
Signs of dehydration Symptoms Dehydration is a deficiency of water in the body. Vomiting, diarrhea, excessive sweating, burns, kidney failure, and use of diuretics may cause dehydration. People feel thirsty, and as dehydration... read more (such as a rapid heart rate, low blood pressure, and dry mouth)
Signs of a serious abdominal disorder (such as a distended abdomen and/or severe tenderness to the touch)
Decreased alertness or any other neurologic abnormalities suggesting a brain disorder
Doctors note any previous abdominal surgery because fibrous bands of scar tissue (adhesions) may have formed and caused an intestinal obstruction Intestinal Obstruction An obstruction of the intestine is a blockage that completely stops or seriously impairs the passage of food, fluid, digestive secretions, and gas through the intestines. The most common causes... read more .
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.
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 Table: Some Causes and Features of Nausea and Vomiting Some Causes and Features of Nausea and Vomiting ).
Possible tests include
Blood and urine tests
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.
Treatment of Nausea and Vomiting
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. If these liquids are tolerated, the amounts are increased gradually. When these increases are tolerated, the person may resume eating normal foods. Carbonated beverages and alcohol should be avoided.
Even when people are slightly dehydrated, doctors usually recommend oral rehydration solutions Treatment Dehydration is a deficiency of water in the body. Vomiting, diarrhea, excessive sweating, burns, kidney failure, and use of diuretics may cause dehydration. People feel thirsty, and as dehydration... read more 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 drugs to relieve nausea (antiemetics) depending on the cause and the severity of the vomiting:
For vomiting caused by motion sickness: Antihistamines (such as dimenhydrinate), scopolamine patches, or both
For mild to moderate symptoms: Prochlorperazine, promethazine, or metoclopramide
For severe vomiting (including vomiting caused by chemotherapy): Dolasetron, ondansetron, or granisetron, or sometimes aprepitant
People whose nausea and vomiting have an obvious cause and who have a normal examination only need treatment of their symptoms.
People with significant dehydration or electrolyte abnormalities usually require intravenous fluids.
Doctors look for signs of severe, sudden changes to the abdomen or disorders within the skull.
Girls and women of childbearing age are tested for pregnancy.