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Nausea and Vomiting

Dr Karen Martin
Reviewed by Dr Karen MartinReviewed on 19.10.2023 | 7 minutes read

Nausea and vomiting are common symptoms that can be caused by various factors such as motion sickness, migraine, anxiety, alcohol, medicines, and recent surgery.  The symptoms associated with nausea depend on the underlying cause.

Some common symptoms include an urge to vomit, or actual vomiting, not feeling like eating, severe headache, abdominal pain, vomiting blood, extreme weakness, high fever (over 38.5°C) blurred vision or eye pain, confusion, or stiff neck.

How does occur?

The mechanism for nausea and vomiting is complex and involves many physiological processes. The vomiting centre in the brainstem controls vomiting. The inner ear, intestines, and chemoreceptor trigger zone (CTZ) send information to the centre.

The brain's CTZ contains dopamine, serotonin, opioid, acetylcholine, and substance P receptors. Activating these receptors can cause nausea and vomiting.

When activated, the CTZ sends signals to the brainstem vomiting centre. The hub coordinates activities that cause vomiting. Increased salivation, deep breathing to prevent aspiration, heaving or retching before vomiting, and pyloric sphincter relaxation, which guards the lower end of the stomach, are examples of these phenomena.

Causes of Nausea and Vomiting

Nausea is usually not a sign of anything serious and goes away on its own.  However, if you are feeling sick and do not feel better in a few days or often feel sick, it is advisable to see a doctor who can look for the cause and suggest treatments. They may prescribe anti-sickness medicine if needed.

Here are some of the most common causes of nausea and vomiting:

Less commonly nausea and vomiting can also be a symptom of some more serious conditions such as meningitis, stroke, brain tumours, hepatitis, pancreatitis, appendicitis, peptic ulcer, gallbladder problems, constipation, and infections.

Associated symptoms and identifying possible causes of nausea and vomiting


Common reasons where nausea and vomiting are associated with diarrhoea include viral gastroenteritis, food poisoning, stress, worry, or anxiety.

Other less common causes include Crohn's disease, cancer, irritable bowel syndrome (IBS), peptic ulcer, lactose intolerance, cyclic vomiting syndrome, and heavy metal toxicity.


Nausea is a common migraine symptom which can occur before, during, or after a migraine headache. It can be severe enough to limit some people's activity. Prescription antiemetics (such as cyclizine or prochlorperazine) may help with migraine-related nausea and vomiting.  Non-drug options such as ginger, peppermint oil, and acupressure may also help.


Benign paroxysmal positional vertigo (BPPV), low blood sugar, pregnancy, anxiety, motion sickness, vestibular migraines, and alcohol can cause nausea and vomiting with dizziness. Treatment for dizziness and nausea varies depending on the cause.


Gastroenteritis, viral or bacterial infections, flu, and food poisoning are common conditions that may result in nausea and vomiting associated with a fever.


Morning sickness is typical in early pregnancy. It can strike at any time and last all day. Research suggests that the placental hormone human chorionic gonadotropin (HCG) may trigger pregnancy nausea and vomiting.

Mild cases of nausea and vomiting in pregnancy are usually harmless. However, untreated severe nausea and vomiting can cause dehydration and depleted electrolytes, affecting blood salts that govern fluid balance.

A doctor or midwife may prescribe medication if these fail, or symptoms are severe.

A doctor may prescribe a short-term antiemetic suitable in some instances if severe nausea and vomiting do not improve despite lifestyle adjustments.

Hyperemesis gravidarum (HG) is a rarer condition that affects around 1 to 3 in every 100 pregnancies. Symptoms include severe nausea, vomiting, dehydration, weight loss, and electrolyte disturbance.  Unlike morning sickness, which can sometimes subside in the later stages, HG can occur for the unlucky few throughout the pregnancy.

Patients should notify their midwife, doctor, or hospital immediately if they are frequently sick and unable to eat.

Nausea and vomiting during pregnancy: self-care tips

Patients experiencing nausea and vomiting during pregnancy, may try the following non-drug options first:

  • getting enough rest,
  • avoiding foods or smells that make them sick,
  • eating small, frequent meals of plain foods,
  • drinking plenty of fluids like water or juice,
  • taking ginger in the form of ginger biscuits or ginger tea,
  • or trying acupressure may help.

In some less severe cases, taking short sips of water to prevent dehydration, eating ginger-containing foods (tea, biscuits), sipping fruit juices, sports drinks, or flat soda drink, and eating small, bland meals when hungry may be helpful.

Consult a doctor immediately if you vomit for over a day or two, cannot keep down fluids, or the vomit is green (bile indicating a bowel blockage).

Motion sickness


You can prevent or lessen the effects of motion sickness by:

  • sitting in the front or centre of a car or boat
  • looking straight ahead at a fixed point like the horizon
  • getting some fresh air if you can
  • closing your eyes and breathing slowly while focusing on your breathing
  • keeping yourself distracted by talking, listening to music, or singing, taking short breaks to get some fresh air, or drinking water
  • taking ginger in the form of ginger biscuits
  • wearing acupressure bands

When to see a doctor

If you have persistent nausea, vomiting, or diarrhoea for several days, or dizziness that keeps coming back, your doctor can investigate the underlying cause(s) and provide appropriate therapies.  

Sudden nausea, tightness or heaviness in the chest, pain radiating to the arms, back, neck, or jaw, and/or difficulty breathing may be signs of a heart attack. In such a situation, call emergency services immediately.



Nausea is a common symptom that usually resolves on its own. There are some non-drug measures you can try that might help, such as:

  • getting plenty of fresh air or using aromatherapy
  • using deep breathing and mindfulness to calm anxiety-related nausea
  • distracting yourself with music or watching a movie
  • taking regular sips of a cold drink or juice
  • taking ginger in the form of ginger biscuits or ginger tea
  • drinking other teas such as peppermint tea, chamomile, or lemon
  • eating smaller, more frequent meals
  • trying acupressure techniques at specific points on the body


Depending on the cause of the nausea and vomiting, there are some treatments that are available at the pharmacy or from your doctor.

Nausea with no known obvious cause should be evaluated by a doctor if it continues, since it is important to know what the cause is, and controlling the nausea could potentially mask a more serious underlying condition.

For acute cases of migraine that are associated with previously diagnosed migraine, products such as Buccastem M (containing 3 mg prochlorperazine) is particularly useful in the short term, since it can be absorbed directly through the buccal area (through the gums into the bloodstream, bypassing the need to swallow the tablets).  Other products such as Pink which contains buclizine combined with paracetamol and codeine is also available at the pharmacy.

For nausea and vomiting due to motion sickness, centrally acting antihistamine-based treatments such as Stugeron tablets (containing cinnarizine 15mg), or Kwells tablets (containing hyoscine) are usually available from most pharmacies.

Other treatments such as cyclizine 50 mg tablets are also available from the pharmacist for non-specific causes of nausea in certain situations.

Injectable versions of cyclizine, or treatments for vestibular conditions that may cause dizziness such as labyrinthitis or vertigo, are available on prescription from the doctor.  Typical medicines may include betahistine 8 mg or 16 mg tablets, cinnarizine 15 mg tablets, or prochlorperazine 5 mg tablets, to name a few.

Nausea and vomiting and risks of dehydration

Nausea and vomiting can cause dehydration due to not drinking enough fluids or vomiting and being unable to retain food and drink.

Where possible, take small sips of water at regular intervals. O.R.S soluble tablets and Dioralyte can also assist in replacing electrolytes and maintaining fluid balance.

Oral rehydration salts help the small intestine absorb more liquids quickly, counteracting dehydration and promoting faster recovery.

Frequent vomiting or diarrhoea can sometimes cause significant dehydration due to excessive fluid loss relative to the amount of fluid intake.  Patients should seek medical attention since they may require anti-sickness medication or IV infusion to aid rec

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Dr Karen Martin
Reviewed by Dr Karen Martin
Reviewed on 19.10.2023
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