Nausea is a sensation of unease and discomfort in the upper stomach with an involuntary urge to vomit. It may precede vomiting, but a person can have nausea without vomiting. When prolonged, it is a debilitating symptom. 

Nausea is a non-specific symptom, which means that it has many possible causes. Some common causes of nausea are motion sickness, dizziness, migraine, fainting, low blood sugar, gastroenteritis (stomach infection) or food poisoning. Nausea is a side effect of many medications including chemotherapy, or morning sickness in early pregnancy. Nausea may also be caused by anxiety, disgust and depression. 

Nausea and vomiting remain undiagnosed in 10% of the cases, with rates about 6% in children and more than 16% in people aged more than 65 years. 

Nausea can have several causes such as:


A number of conditions involving balance such as motion sickness and vertigo can lead to nausea and vomiting.


Gastrointestinal infection is one of the most common causes of acute nausea and vomiting. Chronic nausea may be the presentation of many gastrointestinal disorders, occasionally as the major symptom, such as gastroesophageal reflux disease (a long-term condition where stomach contents come back up into the esophagus resulting in either symptoms or complications), functional dyspepsia (a condition that causes an upset stomach or pain or discomfort in the upper belly), gastroparesis (a condition where the stomach can't empty itself of food in the normal way, causing food to pass through it slowly), peptic ulcer (a break in the lining of the stomach, first part of the small intestine, or occasionally the lower esophagus), celiac disease, Crohn's disease (inflammatory bowel disease), hepatitis, upper gastrointestinal malignancy, and pancreatic cancer. 

Food poisoning

Food poisoning usually causes an abrupt onset of nausea and vomiting one to six hours after ingestion of contaminated food and lasts for one to two days. It is due to toxins produced by bacteria in food. 


Many medications can potentially cause nausea. Some of the most frequently associated include cytotoxic chemotherapy regimens for cancer and other diseases, and general anaesthetic agents.


Nausea may be caused by depression, anxiety disorders and eating disorders. 

Potentially serious

While most causes of nausea are not serious, some serious conditions are associated with nausea. These include: pancreatitis (inflammation of pancreas), small bowel obstruction, appendicitis (inflammation of appendix), cholecystitis (inflammation of the gallbladder), hepatitis (inflammation of the liver), increased intracranial pressure, brain tumors, meningitis, heart attack, carbon monoxide (CO) poisoning and many others. 


Vomiting can be caused by a wide variety of conditions; it may present as a specific response to ailments like gastritis or poisoning, or as a non-specific sequela of disorders ranging from brain tumors and elevated intracranial pressure to overexposure to ionizing radiation. Antiemetics (a drug that is effective against vomiting and nausea) are sometimes necessary to suppress nausea and vomiting. In severe cases, where dehydration develops, intravenous fluid may be required.

Nausea and vomiting together

Very often nausea is accompanied by vomiting. Nausea and vomiting can occure after chemotherapy treatment, after operation with anaesthesia and in pregnant women.

Chemotherapy-induced nausea and vomiting (CINV) is a common side-effect of many cancer treatments. Nausea and vomiting are two of the most feared cancer treatment-related side effects for cancer patients and their families. Since the 1990s, several novel classes of antiemetics have been developed and commercialized, becoming a nearly universal standard in chemotherapy regimens, and helping to better manage these symptoms in a large portion of patients. Efficient mediation of these unpleasant and sometimes crippling symptoms results in increased quality of life for the patient, and better overall health of the patient, and, due to better patient tolerance, more effective treatment cycles.

Postoperative nausea and vomiting

Postoperative nausea and vomiting (PONV) is an unpleasant complication affecting about a third of the 10% of the population undergoing general anaesthesia each year. Medications are thought to stimulate the chemoreceptor trigger zone (CTZ) responsible for development of nausea and vomiting. This area is on the floor of the fourth ventricle and is effectively outside of the blood-brain barrier (separates the circulating blood from the brain extracellular fluid in the central nervous system). This makes it incredibly sensitive to toxin and pharmacological stimulation.

Pregnancy nausea and vomiting

Morning sickness, also called nausea and vomiting of pregnancy (NVP), is a symptom of pregnancy that involves nausea or vomiting. Despite the name, nausea or vomiting can occur at any time during the day. Typically these symptoms occur between the 4th and 16th week of pregnancy. About 10% of women still have symptoms after the 20th week of pregnancy. A severe form of the condition is known as hyperemesis gravidarum and results in weight loss. 

The cause of morning sickness is unknown but may be related to changing levels of the hormone human chorionic gonadotrophin. Diagnosis should only occur after other possible causes have been ruled out.

Nausea and vomiting can be a symptom of diseases of reproduction system such as testicular torsion, orchitis and mumps.

Testicular torsion

Testicular torsion occurs when the spermatic cord (from which the testicle is suspended) twists, cutting off the testicle's blood supply. Testicular torsion usually presents with sudden, severe, testicular pain (in groin and lower abdomen) and tenderness. There is often associated reflectory nausea and vomiting as a result of severe pain.

Mumps and orchitis

Both of diseases are cause by inflammation of the testicles. Mumps are viral origin and orchitis can be caused by bacterial infection. Before the introduction of the mumps vaccine, the mumps virus was the leading cause of viral meningoencephalitis (the inflammation of the membranes that envelop the brain) which is accompanied by nausea and vomiting. Orchitis can cause these symptoms as a nature response to the infection.

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Morning sickness ―sourced from Wikipedia licensed under CC BY- SA 3.0
Nausea ―sourced from Wikipedia licensed under CC BY- SA 3.0
Chemotherapy-induced nausea and vomiting ―sourced from Wikipedia licensed under CC BY- SA 3.0
Postoperative nausea and vomiting ―sourced from Wikipedia licensed under CC BY- SA 3.0
Testicular torsion ―sourced from Wikivisually licensed under CC BY- SA 3.0
Vomiting ―sourced from Wikipedia licensed under CC BY- SA 3.0
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