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June 21, 2018

Vomiting and Nausea - Symptom information, causes and treatment

Vomiting, also known as emesis, is the forceful expulsion of the contents of the stomach via the mouth and occasionally the nose. Nausea is the discomfort or unpleasant feeling which a person experiences before vomiting. It is possible to experience nausea without any vomiting occurring. Nausea and vomiting are both symptoms rather than a disease. 

Vomiting is a natural reflex which the body initiates to protect itself.  If you eat something which is poisonous or contaminated, then vomiting is the body’s way of removing it from your system.

What is vomiting?

The vomiting reflex is controlled by the chemoreceptor trigger zone (CTZ) within the fourth ventricle of the brain. The CTZ has direct access to substances within the bloodstream, which is why poisonous or contaminated food can induce vomiting, but it also works in reverse and allows medications to be easily absorbed, which may be taken to stop or trigger vomiting. The CTZ can also be stimulated and cause vomiting if:

  • the vestibular system in the inner ear is triggered during motion sickness
  • the tenth cranial nerve (vagus nerve) is stimulated in cases of gastroenteritis
  • the back of the throat is irritated which initiates the gag reflex.

Types of vomiting

There are three main types of vomiting. The first, possetting, is only applicable for small infants, and the most common type of vomiting is projectile vomiting. The three types are:

  • Possetting  - when a baby vomits up small amounts after a feed
  • Reflux – in young babies this is very common.  The valve at the top of the stomach is weak and takes time to strengthen.  This allows the contents of the stomach to come back up the esophagus (food pipe).  This can cause stomach discomfort after the baby feeds and some vomiting. As the baby grows and gets older the condition improves and they grow out of it when more solid feeds are taken. Some adults, however, can suffer from reflux.
  • Projectile vomiting - Can occur in all ages, and is forceful vomiting. In babies, this is when the contents of the stomach are returned in a forceful way. The amount of milk or food returned seems a lot compared to posseting and reflux and tends to come out in one amount and forcefully hence the term ‘projectile’.  Babies may occasionally projectile vomit and there may be no cause but if it happens regularly or after ever feed then it's important to seek medical attention immediately in case the baby has a blockage in their stomach or intestine. Projectile vomiting is a red flag symptom for all ages as it can also indicate an obstruction in older children and adults, so if it occurs more than once be sure to consult a health professional.

Causes of vomiting


Common causes of vomiting from Isabel Symptom Checker

There are many causes of vomiting, and they range from a mild infection or motion sickness, to a warning of more serious conditions that need immediate medical attention. We’ve outlined some of the most common conditions associated with vomiting, as well as some red flag diagnoses to look out for.

Digestive Tract Dysfunction

Nausea and vomiting can be seen with any digestive tract dysfunction but the most common is gastroenteritis, or stomach flu, where your stomach and intestines become irritated and inflamed by a viral or bacterial infection.  Other symptoms of gastroenteritis to look out for include diarrhea, stomach pain, stomach cramping, fever, nausea and headache. Other gastrointestinal disorders which induce vomiting include gastroesophageal reflux disease, peptic ulcer disease, Crohn’s disease, irritable bowel syndrome, pancreatitis and liver disease.


Symptoms include sudden pain in the right lower abdomen, pain which worsens if you cough, nausea, vomiting, loss of appetite and low-grade fever.  This is a medical emergency and treatment should be sought immediately if you suspect appendicitis.

Drugs and Toxins

Alcohol, opioid analgesics such as morphine, and chemotherapy medications can cause nausea and vomiting. Exposure to toxins such as those in lead or some foods and plants can induce severe nausea and vomiting.

Central Nervous System Disorders

Infections such as meningitis, encephalitis, migraines, brain tumors, brain haemorrhage and head injuries all occur within the brain, which is where the vomiting center and CTZ is located. This causes an increase of intracranial pressure within the brain, manifesting as severe vomiting and nausea.  These disorders require immediate diagnosis and treatment.

Vestibular (Ear) Disorders

The vestibular apparatus within the inner ear is connected to the vomiting center within the brain. If there is any disruption to this mechanism caused by infection, labyrinthitis or positional vertigo then vomiting can be induced.  The vestibular apparatus is also aggravated during motion sickness.

Psychologic disorders

Functional or psychogenic vomiting can be seen in psychological disorders where the vomiting may be intentional in conditions such as anorexia or bulimia. It can also be unintentional where people are anxious or in a stressful situation, such as school phobia where a child is afraid of going to school.

Cyclic Vomiting Syndrome

This results in severe attacks of vomiting or nausea at regular intervals with no symptoms between attacks.  It normally commences in childhood and can last till adulthood.  Cyclic vomiting in adults has been linked to chronic marijuana use.


As mentioned earlier this is manifested as projectile vomiting. In babies, conditions include pyloric stenosis or intussusception. In adults, the obstruction can be due to the intestine twisting (intestinal volvulus), adhesions, hernias or tumors.


Nausea and vomiting within the first trimester of pregnancy is very common and may be one of the first signs that you have conceived.  Around 7 out of 10 pregnant women experience these symptoms. Occasionally, the nausea and vomiting can become excessive and this is known as hyperemesis gravidarum and often needs hospital treatment to monitor the woman and her fetus.

Vomiting complications

If the cause of the vomiting is not identified and persists then it can become very tiring, uncomfortable and complications can occur:

  • Inhaling the vomit can cause aspiration into the lungs which can lead to breathing problems and infection,
  • Excessive vomiting can lead to a Mallory-Weiss tear in the esophagus lining,
  • Dehydration and abnormalities with the electrolytes in the body.  Babies and children are very prone to this
  • Undernutrition leading to weight loss.

When to consult a health professional

Many cases of nausea and vomiting are self-limiting and will resolve within 24-48 hours but if you experience any of these other signs then you should seek medical attention.

  • dehydration (thirst, dry mouth, little or no urine output, feeling weak)
  • stiff neck, confusion, headache, decreased consciousness
  • constant stomach pain
  • stomach tenderness when touched
  • bloody stools
  • swollen stomach
  • bloody vomit
  • recent head injury

If the cause of the vomiting is deemed to have no serious underlying disorder and the person is not dehydrated, then taking small amounts of liquid, preferably water, should be taken regularly, or as often as the patient can manage. Oral rehydration solutions can be taken if the vomiting is prolonged.  Medications can be used to help alleviate vomiting if a health care professional deems it necessary.

As you can see the causes of vomiting are numerous and varied. It's important that other symptoms are considered and the severity and nature of the vomiting is determined. Using the Isabel Symptom Checker to describe your vomiting symptoms may assist you with researching possible conditions you could have, help you decide where to seek medical treatment, and help you discuss the possibilities with your doctor.


Mandy Tomlinson

Mandy Tomlinson

Mandy has worked for Isabel Healthcare since 2000. Prior to this, she was a Senior Staff Nurse on the Pediatric Infectious disease ward and high dependency unit at one of London's top hospitals, St Mary’s in Paddington which is part of Imperial College Healthcare NHS Trust. Her experience in the healthcare industry for the past 28 years in both the UK and USA means she's a vital resource for our organization. Mandy currently lives and works in Scottsdale, Arizona.


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