Nausea is a sensation of unease and discomfort in the upper stomach

Stomach

The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...

 with an involuntary urge to vomit. It often, but not always, precedes vomiting. A person can suffer nausea without vomiting.

Some common causes of nausea are motion sickness

Motion sickness

Motion sickness or kinetosis, also known as travel sickness, is a condition in which a disagreement exists between visually perceived movement and the vestibular system's sense of movement...

, dizziness

Dizziness

Dizziness refers to an impairment in spatial perception and stability. The term is somewhat imprecise. It can be used to mean vertigo, presyncope, disequilibrium, or a non-specific feeling such as giddiness or foolishness....

, fainting, gastroenteritis

Gastroenteritis

Gastroenteritis is marked by severe inflammation of the gastrointestinal tract involving both the stomach and small intestine resulting in acute diarrhea and vomiting. It can be transferred by contact with contaminated food and water...

 (stomach infection) or food poisoning. Side effects of many medications including cancer chemotherapy, nauseants

Nauseant

A nauseant is a substance or an agent that is used to generate the tendency to vomit. Tobacco and egg white are nauseous to children, and produce sickness at the stomach. Nauseants are akin to direct emetics....

 or morning sickness

Morning sickness

Morning sickness, also called nausea gravidarum, nausea, vomiting of pregnancy , or pregnancy sickness is a condition that affects more than half of all pregnant women. Related to increased oestrogen levels, a similar form of nausea is also seen in some women who use hormonal contraception or...

 in early pregnancy. Nausea may also be caused by stress

Stress (biology)

Stress is a term in psychology and biology, borrowed from physics and engineering and first used in the biological context in the 1930s, which has in more recent decades become commonly used in popular parlance...

, anxiety

Anxiety

Anxiety is a psychological and physiological state characterized by somatic, emotional, cognitive, and behavioral components. The root meaning of the word anxiety is 'to vex or trouble'; in either presence or absence of psychological stress, anxiety can create feelings of fear, worry, uneasiness,...

, disgust

Disgust

Disgust is a type of aversion that involves withdrawing from a person or object with strong expressions of revulsion whether real or pretended. It is one of the basic emotions and is typically associated with things that are regarded as unclean, inedible, infectious, gory or otherwise offensive...

, worry

Worry

Worry is thoughts, images and emotions of a negative nature in whichmental attempts are made to avoid anticipated potential threats. As an emotion it is experienced as anxiety or concern about a real or imagined issue, usually personal issues such as health or finances or broader ones such as...

 and depression

Depression (mood)

Depression is a state of low mood and aversion to activity that can affect a person's thoughts, behaviour, feelings and physical well-being. Depressed people may feel sad, anxious, empty, hopeless, helpless, worthless, guilty, irritable, or restless...

.

Medications taken to prevent nausea are called antiemetic

Antiemetic

An antiemetic is a drug that is effective against vomiting and nausea. Antiemetics are typically used to treat motion sickness and the side effects of opioid analgesics, general anaesthetics, and chemotherapy directed against cancer....

s and include diphenhydramine

Diphenhydramine

Diphenhydramine hydrochloride is a first-generation antihistamine possessing anticholinergic, antitussive, antiemetic, and sedative properties which is mainly used to treat allergies. Like most other first-generation antihistamines, the drug also has a powerful hypnotic effect, and for this reason...

, metoclopramide

Metoclopramide

Metoclopramide is an antiemetic and gastroprokinetic agent. It is commonly used to treat nausea and vomiting, to facilitate gastric emptying in people with gastroparesis, and as a treatment for the gastric stasis often associated with migraine headaches.-Medical uses:Metoclopramide is commonly...

 and ondansetron

Ondansetron

Ondansetron is a serotonin 5-HT3 receptor antagonist used mainly as an antiemetic , often following chemotherapy. Its effects are thought to be on both peripheral and central nerves...

.

Differential diagnosis

The causes of nausea are many. One organization listed 700 in 2009. Gastrointestinal infections

Gastroenteritis

Gastroenteritis is marked by severe inflammation of the gastrointestinal tract involving both the stomach and small intestine resulting in acute diarrhea and vomiting. It can be transferred by contact with contaminated food and water...

 (37%) and food poisoning are the two most common causes. While side effects from medications (3%) and pregnancy are also relatively frequent. In 10% of people the cause remains unknown.

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

Bacteria

Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

 in food.

Medications

Many medications can potentially cause nausea. Some of the most frequently associated include cancer chemotherapy

Chemotherapy

Chemotherapy is the treatment of cancer with an antineoplastic drug or with a combination of such drugs into a standardized treatment regimen....

 regimens and general anaesthetic agents

General anaesthesia

General anaesthesia is a state of unconsciousness and loss of protective reflexes resulting from the administration of one or more general anaesthetic agents...

.

Pregnancy

Nausea or "morning sickness

Morning sickness

Morning sickness, also called nausea gravidarum, nausea, vomiting of pregnancy , or pregnancy sickness is a condition that affects more than half of all pregnant women. Related to increased oestrogen levels, a similar form of nausea is also seen in some women who use hormonal contraception or...

" is common during early pregnancy

Pregnancy

Pregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...

 but may occasionally continue into the second and third trimesters. In the first trimester nearly 80% of women have some degree of nausea. Pregnancy should therefore be considered as a possible cause of nausea in any women of child bearing age. While usually it is mild and self limiting severe cases known as hyperemesis gravidarum

Hyperemesis gravidarum

Hyperemesis gravidarum is a severe form of morning sickness, with "unrelenting, excessive pregnancy-related nausea and/or vomiting that prevents adequate intake of food and fluids." Hyperemesis is considered a rare complication of pregnancy but, because nausea and vomiting during pregnancy exist...

 may require treatment.

Disequilibrium

A number of conditions involving balance such as motion sickness

Motion sickness

Motion sickness or kinetosis, also known as travel sickness, is a condition in which a disagreement exists between visually perceived movement and the vestibular system's sense of movement...

 and vertigo

Vertigo (medical)

Vertigo is a type of dizziness, where there is a feeling of motion when one is stationary. The symptoms are due to a dysfunction of the vestibular system in the inner ear...

 can lead to nausea and vomiting.

Stress and depression

Nausea may be caused by stress

Stress (biology)

Stress is a term in psychology and biology, borrowed from physics and engineering and first used in the biological context in the 1930s, which has in more recent decades become commonly used in popular parlance...

 and depression

Depression (mood)

Depression is a state of low mood and aversion to activity that can affect a person's thoughts, behaviour, feelings and physical well-being. Depressed people may feel sad, anxious, empty, hopeless, helpless, worthless, guilty, irritable, or restless...

.

Potentially serious

While most causes of nausea are not serious, some serious causes do occur. These include: diabetic ketoacidosis

Diabetic ketoacidosis

Diabetic ketoacidosis is a potentially life-threatening complication in patients with diabetes mellitus. It happens predominantly in those with type 1 diabetes, but it can occur in those with type 2 diabetes under certain circumstances...

, brain tumor

Brain tumor

A brain tumor is an intracranial solid neoplasm, a tumor within the brain or the central spinal canal.Brain tumors include all tumors inside the cranium or in the central spinal canal...

, surgical problems, pancreatitis

Pancreatitis

Pancreatitis is inflammation of the pancreas. It occurs when pancreatic enzymes that digest food are activated in the pancreas instead of the small intestine. It may be acute – beginning suddenly and lasting a few days, or chronic – occurring over many years...

, small bowel obstruction, meningitis

Meningitis

Meningitis is inflammation of the protective membranes covering the brain and spinal cord, known collectively as the meninges. The inflammation may be caused by infection with viruses, bacteria, or other microorganisms, and less commonly by certain drugs...

, appendicitis

Appendicitis

Appendicitis is a condition characterized by inflammation of the appendix. It is classified as a medical emergency and many cases require removal of the inflamed appendix, either by laparotomy or laparoscopy. Untreated, mortality is high, mainly because of the risk of rupture leading to...

, cholecystitis

Cholecystitis

-Signs and symptoms:Cholecystitis usually presents as a pain in the right upper quadrant. This is known as biliary colic. This is initially intermittent, but later usually presents as a constant, severe pain. During the initial stages, the pain may be felt in an area totally separate from the site...

, Addisonian crisis, Choledocholithiasis (from gallstones) and hepatitis

Hepatitis

Hepatitis is a medical condition defined by the inflammation of the liver and characterized by the presence of inflammatory cells in the tissue of the organ. The name is from the Greek hepar , the root being hepat- , meaning liver, and suffix -itis, meaning "inflammation"...

, as a sign of carbon monoxide poison and many others.

Diagnostic approach

Often no investigations are needed, however basic lab tests may be appropriate. If a bowel obstruction is possible, abdominal x-rays may be useful.

Treatment

If dehydration is present due to loss of fluids from severe vomiting and/or accompanying diarrhea

Diarrhea

Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...

, rehydration with oral electrolyte solutions is preferred. If this is not effective or possible, intravenous rehydration may be required.

Medications

Dimenhydrinate

Dimenhydrinate

Dimenhydrinate is an over-the-counter drug used to prevent nausea and motion sickness...

 (Gravol) is an inexpensive and effective medication for preventing postoperative nausea and vomiting. Meclozine

Meclozine

Meclozine is an antihistamine considered to be an antiemetic. It is sold under the brand names Bonine, Bonamine, Antivert, Postafen, Sea Legs, and Dramamine . Emesafene is a combination of meclozine and pyridoxine...

 is another antihistamine

Antihistamine

An H1 antagonist is a histamine antagonist of the H1 receptor that serves to reduce or eliminate effects mediated by histamine, an endogenous chemical mediator released during allergic reactions...

 antiemetic

Antiemetic

An antiemetic is a drug that is effective against vomiting and nausea. Antiemetics are typically used to treat motion sickness and the side effects of opioid analgesics, general anaesthetics, and chemotherapy directed against cancer....

. In certain people, cannabinoids

Cannabinoids

Cannabinoids are a class of chemical compounds that include the phytocannabinoids , and chemical compounds that mimic the actions of phytocannabinoids or have a similar structure...

 may be effective in reducing chemotherapy associated nausea and vomiting. Ondansetron

Ondansetron

Ondansetron is a serotonin 5-HT3 receptor antagonist used mainly as an antiemetic , often following chemotherapy. Its effects are thought to be on both peripheral and central nerves...

 (Zofran) is effective for nausea and vomiting but is expensive. Pyridoxine

Pyridoxine

Pyridoxine is one of the compounds that can be called vitamin B6, along with pyridoxal and pyridoxamine. It differs from pyridoxamine by the substituent at the '4' position. It is often used as 'pyridoxine hydrochloride'.-Chemistry:...

 or metoclopramide

Metoclopramide

Metoclopramide is an antiemetic and gastroprokinetic agent. It is commonly used to treat nausea and vomiting, to facilitate gastric emptying in people with gastroparesis, and as a treatment for the gastric stasis often associated with migraine headaches.-Medical uses:Metoclopramide is commonly...

 are the first line treatments for pregnancy related nausea and vomiting.
Medical marijuana may be prescribed where allowed for certain indications.

Prognosis

While short-term nausea and vomiting are generally harmless, they may sometimes indicate a more serious condition. When associated with prolonged vomiting, it may lead to dehydration

Dehydration

In physiology and medicine, dehydration is defined as the excessive loss of body fluid. It is literally the removal of water from an object; however, in physiological terms, it entails a deficiency of fluid within an organism...

 and/or dangerous electrolyte

Electrolyte

In chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....

 imbalances.

Epidemiology

Nausea and or vomiting

Vomiting

Vomiting is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose...

is the main complaint in 1.6% of visits to family physicians in Australia. However only 25% of people with nausea visit their family physician. It is most common in those 15–24 years old and less common in other ages.