Nausea and Vomiting: Causes, Symptoms, Diagnosis, Treatment, Prevention and Prognosis

man with Nausea and Vomiting


Nausea is an unpleasant feeling that a person wants to vomit. On the other hand, vomiting is a process of ejecting the contents of the stomach through the mouth. Generally, vomiting has protective purposes, such as the removal of harmful substances in the stomach. However, it can occur from inflammatory processes and unrelated infections in the body.

The abdominal wall muscles contract during vomiting. This creates pressure within the abdomen necessary for retching. Retching is also known as “dry heaving” and can occur even if a person does not vomit. It can also occur before a person vomits or after. Similarly, nausea can also occur even if the person does not vomit. It may also occur before the person vomits.

Vomiting should be differentiated from the act of regurgitating food. Regurgitation is effortless and it allows swallowed food in the stomach to be transferred back to the mouth via the esophagus. When the regurgitated material has a sour and bitter taste, it may be a manifestation of gastroesophageal reflux disease (GERD). When the contents of the stomach taste the same as ingested food, there may be a problem with the movement of food from the esophagus to the stomach. Rumination is another phenomenon that may be mistaken for vomiting. However, the two conditions are unrelated because rumination is a learned behavior that occurs when the person re-chews and re-swallows food, which he may consider pleasurable.


There are many things that can cause nausea and vomiting. One of the causes can be medications. Almost any medication lists nausea and vomiting as potential side effects. However, there are certain medications that are well-known to cause nausea and vomiting, such as drugs used for chemotherapy to treat cancer and anesthetic agents. Any use of medications must be with the advice of a doctor.

Infections in the gastrointestinal tract may also cause nausea and vomiting. Viruses or bacteria that have invaded any part of the gastrointestinal tract can cause a person to vomit. Often, vomiting is a response to the presence of these pathogens. Gall bladder infections, called cholecystitis, diverticulitis, which occurs in the intestine, and appendicitis are all infections that can potentially cause nausea and vomiting.

Infections outside of the gastrointestinal tract can also be reasons for a person to feel nauseous and to vomit. These infections include pneumonia, infections in the coverings of the brain (meningitis), infections in the ear, and bladder and kidney infections.

One of the most well-known causes of nausea and vomiting are toxins found in food. Food poisoning causes nausea and vomiting. In this instance, the body tries to eject the toxin from the stomach by contracting the muscles of the abdominal wall. Food toxins include botulinum, which is often found in canned food, and salmonella, found in raw food.

Sometimes, nausea and vomiting are side effects of physiological processes. For instance, nausea and vomiting are common during the first three months of pregnancy, when the hormone levels of women are high. Alcohol intoxication is well-known to lead to nausea and vomiting. Motion sickness is another cause.

Other lesser known causes of nausea and vomiting include intestinal blockages. This can be due to intestinal ulcers, tumors, or cancers. Crohn’s disease is another cause for nausea and vomiting. Migraine headaches, due to the pain and pressure, can cause nausea and vomiting as well.


The symptoms of nausea are quite known. Almost everyone has experienced nausea and vomiting at least once in their lives. Nausea produces a “queasy” feeling in the stomach, or of being sick. Nausea may occur accompanied by vomiting or not. These symptoms may manifest alongside a sensation of sweating, flushing, light-headedness, salivation, and upper abdominal discomfort. Salivation is a reaction of the salivary glands in anticipation of the food that will be vomited. In addition, it is present during vomiting because the acids in the stomach stimulate the salivary glands to produce saliva.

Other symptoms of vomiting include bending over or the inability to stand still and straight. The contraction of the muscles of the abdominal wall causes this feeling. Usually, the muscles contract and the person is unable to stand straight. Aside from these, a person who is vomiting will feel better after vomiting, unless he needs to vomit again. Heartburn is associated with vomiting, since the contents of the stomach are ejected back into the mouth, passing through the esophagus.


A diagnosis of the underlying cause of nausea and vomiting must begin with the three-step approach recommended by the American Gastroenterological Association. First, the consequences of nausea and vomiting should be treated. These include dehydration and electrolyte imbalances. Next, the underlying cause should be identified and specific therapies used. Third, if no specific cause can be identified, then empiric therapy should be used to treat the symptoms. Due to the broad range of possible underlying symptoms, this ordered approach is essential.

In order to identify the exact etiology of nausea and vomiting, the patient’s symptoms must be clearly defined. They must first be differentiated from rumination and regurgitation. A detailed history of the patient’s symptoms can provide the doctor with clues to a diagnosis. The duration of symptoms should be determined since the durations differ significantly for sudden (acute) symptoms and chronic symptoms.

Next, a physical examination should be conducted. This should focus on initial signs, such as dehydration. Skin turgor, or how fast the skin rebounds after being pinched, should also be evaluated. Mucous membranes should be checked for signs of dehydration. Orthostatic changes and hypotension should be observed if they are present. Inflammation of the lymph nodes (lymphadenopathy), yellowing (jaundice), and signs of thyroid problems should be noted. A neurologic examination is also essential for diagnosis.


After the warning signs of nausea and vomiting have been identified and the proper emergency interventions have also been given, the primary goal of treatment is to assess the patient’s electrolyte and fluid status. Electrolytes and fluids need to be replaced to prevent dehydration and the possible complications of electrolyte imbalance, such as arrhythmia (abnormal heart rhythm). A doctor may also prescribe a liquid or low-fat diet since fatty foods delay the time it takes for the stomach to empty.

If the exact cause of nausea and vomiting are identified, then therapies that target the cause can be started. If the evaluation will be delayed, the doctor may prescribe drugs to ease the patient’s discomfort. The first-line drug for this purpose is chlorpromazine, which is effective for reducing nausea and vomiting.

Metoclopramide, which is a pro-kinetic drug, may also be beneficial. Drugs that antagonize serotonin, such as ondansetron, may also be used. However, they are costly and may not be feasible for long-term treatment.

If nausea is not controlled by metoclopramide, which is an anti-emetic, then another anti-emetic drug can be added, especially if nausea continues for another 48 hours. The initial drug should not be stopped. Antiemetics should be given regularly for chronic nausea. A variety of routes of administration may be tried to relieve symptoms.

Other non-pharmacological treatments can be used. These include environmental modification, which usually consists of eliminating strong odors and sights from the immediate surroundings. Air fresheners may also be used. Maintaining good oral hygiene may also help resolve nausea and vomiting. Acupuncture or stimulating certain pressure points have been found to have limited benefit in treating nausea and vomiting. Hypnosis and visualization have been successfully used. Distractions may also be used. 


When nausea and vomiting occur due to a known cause, such as by being in a car or plane, then prevention is possible by taking medications beforehand. Medications must only be taken with the advice of a doctor. Other situations where nausea and vomiting can be prevented include prior to chemotherapy or before anesthesia is given for surgery. Symptoms that are caused by certain drugs usually resolve on their own after the drug is stopped. The same mechanism holds true for nausea and vomiting caused by toxins. Morning sickness, or nausea and vomiting caused by pregnancy, will resolve on its own as the mother moves to the second and third trimesters. However, nausea and vomiting due to other reasons, such as functional problems, endocrine problems, or psychiatric problems, are more difficult to treat. Chronic drugs may be needed in these cases. 


The prognosis of nausea and vomiting is usually good if treatment is given early on. These usually resolve on their own when the specific cause stops or is removed. However, chronic nausea and vomiting may erode the enamel on teeth, causing dental caries. Vomiting may also harm the esophagus and lead to open sores known as ulcers. These can be painful and may eventually lead to trouble swallowing or even throat cancer (Barrett’s esophagus). However, with early treatment, both nausea and vomiting can be resolved and the prognosis is favorable for most patients in whom therapy is initiated by a qualified physician.