Nausea / Vomiting
Symptoms, Causes & Treatment
Nausea and vomiting are among the most common symptoms in medicine, arising from many different systems. Most causes are benign and self-limiting, but some require urgent investigation and treatment.
What are Nausea & Vomiting?
Nausea is the unpleasant sensation of the urge to vomit. Vomiting is the forceful expulsion of gastric contents through the mouth. Together they are caused by activation of the vomiting centre in the brainstem, which receives input from the gut, vestibular system, chemoreceptor trigger zone, and higher cortical centres. Identifying the underlying cause determines appropriate treatment.
Symptoms of Nausea & Vomiting
Nausea and vomiting can be acute or chronic, and may be accompanied by other symptoms that help identify the cause.
Nausea (feeling of sickness) · Vomiting (expulsion of stomach contents) · Retching without vomiting · Loss of appetite · Abdominal discomfort or pain · Pallor and sweating · Dizziness or lightheadedness accompanying nausea
Vomiting blood or coffee-ground material · Projectile vomiting · Vomiting with severe headache and neck stiffness · Signs of dehydration (dry mouth, reduced urine, confusion) · Persistent vomiting lasting more than 24 hours · Vomiting with severe abdominal pain
Vomiting blood · Projectile vomiting with severe headache and neck stiffness · Signs of severe dehydration · Vomiting with chest pain — call 999 or attend A&E immediately.
What Causes Nausea & Vomiting?
Nausea and vomiting have multiple causes spanning GI, vestibular, metabolic, neurological, and pharmacological origins.
Nausea and vomiting during pregnancy (morning sickness) affects 80% of pregnant women, peaking at 8–12 weeks. Hyperemesis gravidarum is severe vomiting causing dehydration and weight loss requiring hospital treatment.
Vestibular dysfunction — including BPPV, labyrinthitis, and motion sickness — activates the chemoreceptor trigger zone through the vestibulo-cerebellar pathway, causing nausea and vomiting. Anti-emetics and vestibular rehabilitation are effective.
Acute gastroenteritis (norovirus, rotavirus, Campylobacter) causes sudden-onset nausea, vomiting, and diarrhoea. Most cases resolve within 24–72 hours with oral rehydration. Antibiotic treatment is only required for specific bacterial pathogens.
Chemotherapy, radiotherapy, opioids, NSAIDs, antibiotics, digoxin, and many other medications cause nausea through central or peripheral mechanisms. A medication review and anti-emetic therapy address this.
Gastroparesis — delayed gastric emptying — causes persistent nausea, vomiting, bloating, and early satiety. It most commonly occurs in diabetes, Parkinson’s disease, and following vagal nerve damage. Diagnosed by gastric emptying scintigraphy.
Raised intracranial pressure, meningitis, migraine, and posterior fossa lesions all cause central nausea and vomiting through the vomiting centre. New vomiting with headache and neck stiffness is an emergency.
Key Risk Factors
Diagnosing Nausea & Vomiting
Pregnancy must be excluded in all women of reproductive age. Systemic blood tests, vestibular assessment, and imaging identify the underlying cause in most cases.
Treatment for Nausea & Vomiting
Treatment targets the underlying cause. Anti-emetics control symptoms. Oral rehydration salts prevent dehydration. Specific treatments address gastroparesis, vestibular causes, and chemotherapy-induced nausea.
Supportive Measures
Sip cold clear fluids slowly. Eat small frequent meals of bland foods. Rest in a cool environment. Ginger tea and acupressure wristbands help motion sickness and pregnancy nausea. Avoid strong smells. Stay hydrated to prevent dehydration.
Chronic & Recurrent Nausea
Chronic nausea requires investigation to identify the underlying cause. Gastroparesis, functional dyspepsia, and vestibular migraine all require specialist input. Cyclical vomiting syndrome is treated with tricyclics and migraine preventives. Psychological nausea responds to CBT and low-dose amitriptyline.
When to Seek Help
Vomiting blood or coffee-ground material · Projectile vomiting with severe headache · Severe dehydration (no urine, confusion) · Vomiting with chest pain — call 999 immediately.
See a GP if nausea or vomiting has lasted more than 2–3 weeks, is associated with weight loss, or is not explained by a known cause. Pregnancy must always be excluded in women of reproductive age.
Preventing Nausea & Vomiting
Many causes of nausea are preventable through medication management, dietary strategies, and early treatment.
If pregnant, eat small frequent meals. Ginger tea, ginger biscuits, and vitamin B6 (10mg TDS) are effective and safe for morning sickness. Avoid smells and foods that trigger nausea. Rest when needed.
Take prescribed anti-emetics before chemotherapy sessions. Prophylactic ondansetron, dexamethasone, and NK1 receptor antagonists dramatically reduce chemotherapy-induced nausea.
For motion sickness: face forward in the direction of travel, focus on the horizon, and take hyoscine (Kwells) or cinnarizine 1 hour before travel. Avoid reading. Fresh air and cool temperatures help.
Review all medications that cause nausea with your GP: opioids, antibiotics, NSAIDs, and metformin are among the most common. Switching formulation, adjusting timing with food, or changing agent may help.
Optimise blood glucose control in diabetes (HbA1c below 53 mmol/mol) to prevent diabetic gastroparesis. Once gastroparesis is established, small frequent meals of low-fat, low-fibre foods are better tolerated.
If you suspect central causes of nausea (severe headache, neck stiffness, neurological symptoms), seek emergency assessment immediately. Do not delay for nausea accompanying severe headache.
Getting Treatment
A GP can assess nausea, exclude serious causes, and prescribe anti-emetics. Hyperemesis gravidarum and severe dehydration require hospital admission. An online consultation is appropriate for mild persistent nausea without alarm features.
Expert clinical advice, when you need it.
Nausea & Vomiting — Frequently Asked Questions
Nausea has many causes: gastrointestinal infection, pregnancy, vestibular disorders (BPPV, motion sickness), medication side effects, migraine, and metabolic conditions (kidney disease, liver disease, hypercalcaemia). Persistent nausea without an obvious cause always requires a GP assessment to exclude serious conditions.
Seek emergency care if nausea is accompanied by sudden severe headache, neck stiffness, chest pain, severe abdominal pain, vomiting blood or material resembling coffee grounds, or signs of significant dehydration. These may indicate meningitis, heart attack, GI haemorrhage, or other serious conditions.
Nausea in the first trimester (morning sickness) is extremely common, affecting 80% of pregnant women. It typically peaks at 8–12 weeks. Ginger, vitamin B6, small frequent meals, and cyclizine (prescribed by a GP) are effective. Hyperemesis gravidarum (severe, persistent vomiting) requires hospital admission for IV fluids.
Ginger tea or ginger biscuits, eating small frequent meals, staying well hydrated with cold clear fluids, resting in a cool environment, avoiding strong smells, and acupressure wristbands (Sea-Bands) can all reduce nausea. Metoclopramide or cyclizine can be prescribed by a GP if conservative measures are insufficient.
Gastroparesis is delayed emptying of the stomach, causing persistent nausea, vomiting, early satiety, and bloating. It most commonly occurs in people with long-standing diabetes. It is diagnosed by gastric emptying scintigraphy. Small frequent low-fat meals and prokinetic medications (domperidone, metoclopramide) are the main treatments.
Many medications cause nausea: opioids, antibiotics (metronidazole, erythromycin), NSAIDs, metformin, SSRIs, digoxin, and chemotherapy are among the most common. Taking medications with food, switching formulations, or choosing alternative agents can reduce medication-related nausea. Discuss with your GP before stopping prescribed medication.
See a GP if nausea has lasted more than 2–3 weeks, is associated with unexplained weight loss, is accompanied by vomiting blood, or is not explained by an obvious cause. Pregnancy should always be excluded in women of reproductive age. An online GP consultation is a convenient first step.
Yes. Stress, anxiety, and depression all cause nausea through the gut-brain axis. Psychogenic nausea without organic cause is a recognised diagnosis treated with relaxation techniques, CBT, and low-dose tricyclics. All organic causes must be excluded before attributing nausea to a psychological cause.