Quick answer. Nausea and vomiting are most often caused by gastroenteritis, food poisoning, pregnancy, migraine or medication, and usually settle on their own. The biggest red flags are being unable to keep fluids down, vomiting blood or green bile, or vomiting with severe abdominal pain, a stiff neck or after a head injury.
Feeling sick (nausea) and throwing up (vomiting) are among the most common symptoms doctors in Singapore see. Most of the time they are caused by a short-lived stomach bug or something that did not agree with you, and they pass within a day or two with rest and fluids. The body uses vomiting to clear out something harmful, so a single episode is rarely a cause for alarm.
However, nausea and vomiting can also signal problems beyond the stomach, including pregnancy, migraine, inner-ear conditions, medication side effects and, less commonly, serious issues such as a bowel obstruction or raised pressure in the brain. Knowing which warning signs to watch for helps you decide whether to manage at home, see a doctor, or seek emergency care.
At a glance
| Likely cause | Typical features | What to do |
|---|---|---|
| Gastroenteritis | Vomiting with diarrhoea and cramps, often after contact with a sick person | Rest, sip fluids and oral rehydration; usually settles in a day or two |
| Food poisoning | Onset hours after a suspect meal, may affect others who ate the same food | Hydrate; see a doctor if symptoms are severe or prolonged |
| Pregnancy | Morning or all-day nausea in early pregnancy ('morning sickness') | Eat small frequent meals; see a doctor if severe or you cannot keep fluids down |
| Migraine | Nausea with a throbbing headache, light or sound sensitivity | Rest in a dark, quiet room; review recurrent migraine with a doctor |
| Medication or motion | Nausea after a new medicine, or during travel by car, boat or plane | Ask your doctor about alternatives; use motion-sickness remedies |
Red flags: when to seek urgent care
Most nausea and vomiting is harmless, but some signs need urgent attention. Call 995 or go to the nearest emergency department if vomiting follows a head injury, or comes with a stiff neck and fever, a sudden severe headache, confusion, or chest pain.
- Cannot keep any fluids down or shows signs of dehydration (very little urine, dizziness, dry mouth, lethargy)
- Vomiting blood, or material that looks like coffee grounds
- Green or yellow bile with severe abdominal pain and a swollen, tender belly (possible bowel obstruction)
- Severe, constant abdominal pain
- Projectile or persistent vomiting that will not stop
Babies, young children and the elderly dehydrate quickly, so seek care earlier for them.
Gastroenteritis and food poisoning
A stomach bug (viral gastroenteritis) is the most common reason for sudden vomiting, often together with diarrhoea and cramps. It spreads easily through contaminated hands and surfaces. Food poisoning from bacteria usually begins within hours of eating contaminated food and may affect several people who shared the same meal, which is common after buffets or outdoor functions in Singapore’s warm climate.
Both usually settle within a day or two. Rest your stomach for a short while, then sip small amounts of water or oral rehydration salts often rather than drinking a lot at once. Reintroduce plain foods such as rice, porridge or biscuits as you feel better. See a doctor if you cannot keep fluids down or symptoms are severe.
Pregnancy and hormonal causes
Nausea and vomiting in early pregnancy, often called morning sickness, is very common and can occur at any time of day. It usually improves after the first trimester. Eating small, frequent meals, keeping plain biscuits by the bed, and staying hydrated can help. A severe form called hyperemesis gravidarum causes persistent vomiting, dehydration and weight loss and needs medical care, sometimes in hospital.
If you are of childbearing age and have unexplained nausea, a pregnancy test is a sensible first step. Always tell your doctor if you are or might be pregnant before taking any medication.
Migraine, inner-ear and medication causes
Migraine commonly causes nausea and vomiting alongside a throbbing headache and sensitivity to light or sound. Inner-ear problems such as labyrinthitis or vertigo can cause nausea with a strong sense of spinning, often made worse by head movement. Motion sickness during travel works in a similar way.
Many medicines list nausea as a side effect, including some painkillers, antibiotics and treatments such as chemotherapy. If nausea starts soon after a new medicine, speak to your doctor rather than stopping it on your own. Recurrent migraine or persistent vertigo should be reviewed so the underlying cause can be treated.
More serious causes to be aware of
Occasionally vomiting signals a serious problem. A bowel obstruction, where the intestine is blocked, causes vomiting (sometimes of green bile), a swollen, painful abdomen and an inability to pass wind or stool, and needs emergency care. Raised pressure in the brain, for example after a head injury or from another cause, can produce vomiting with severe headache, drowsiness or confusion.
Other causes include appendicitis, gallstones, pancreatitis and severe infections. Vomiting blood or coffee-ground material suggests bleeding in the upper digestive tract and is a medical emergency. Any of these warning signs means you should be assessed urgently.
Which specialist should you see?
For short-lived nausea and vomiting, your GP or polyclinic is the right place to start, and most cases need only fluids and rest. If vomiting is recurrent, persistent, or linked to digestive symptoms such as reflux, abdominal pain or weight loss, a gastroenterologist can investigate the gut and digestive causes. For emergency signs, such as vomiting blood, green bile with severe pain, a head injury, or a stiff neck with fever, call 995 or go to the nearest hospital.
Related guides
- Best Gastroenterology Clinics in Singapore — our editorial shortlist
- gastroenterology clinics directory
- Find a gastroenterologist
- Find a gastroenterologist
- Find a gastroenterologist
Sources
- HealthHub Singapore – Vomiting
- NHS – Feeling sick (nausea)
- Mayo Clinic – Nausea and vomiting
- NHS – Bowel obstruction
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