Seek Urgent Care IfVomiting blood (haematemesis), severe abdominal pain, signs of dehydration (no urine >8 hours, sunken eyes, very dry mouth), or high fever with stiff neck.

Common Causes

Cause	Clues	Duration
Viral gastroenteritis	Diarrhoea, stomach cramps, low-grade fever	1–3 days
Food poisoning	Sudden onset, possible others affected	Hours–2 days
Morning sickness	Pregnancy, worse on empty stomach	Weeks–months
Migraine	Headache, light/sound sensitivity	Hours
Medications	After starting new drug (e.g. opioids, metformin)	Varies
Motion sickness	During travel	During exposure
Appendicitis	Right lower abdo pain, fever	Progressive
Bowel obstruction	Distension, no bowel movement, severe pain	Progressive

Oral RehydrationSmall sips of water or oral rehydration solution every 5–10 minutes are more effective than large gulps when vomiting. Ice chips can also help maintain hydration.

How long should vomiting last before seeing a doctor?

Most viral vomiting resolves in 24–48 hours. See a doctor if it persists beyond 48 hours, if you can't keep any fluids down, or if red-flag symptoms are present.

Is blood in vomit always serious?

Yes. Vomited blood (or coffee-ground material) always warrants emergency assessment. Causes include peptic ulcer, oesophageal varices, or Mallory-Weiss tear.

What can I eat after vomiting?

Once settled, start with plain crackers, toast, bananas, or rice (BRAT diet). Avoid dairy, fatty, or spicy foods until fully recovered.

Can anxiety cause nausea?

Yes. Anxiety activates the gut-brain axis, causing nausea, stomach cramps, or diarrhoea. This is commonly seen before stressful events.

How long it has lasted changes what matters

Duration is the single most useful piece of information. Nausea and vomiting lasting under 48 hours is usually infective or dietary and needs attention to fluids rather than investigation. Beyond about a week, the likely causes shift towards medication effects, pregnancy, gastro-oesophageal reflux, gallbladder disease, gastroparesis in long-standing diabetes, and less commonly raised pressure inside the skull. Vomiting that has come and gone for months, particularly if it relates to meals, points elsewhere again, towards obstruction, ulcer disease or a motility problem.

Features that change the urgency

Blood in the vomit, whether fresh red or dark like coffee grounds, needs urgent assessment.
Vomiting with severe abdominal pain, especially if the abdomen is rigid or tender to release, or if you cannot pass wind or stool.
Vomiting with a severe headache, neck stiffness or new confusion, or vomiting that is worse on waking and unaccompanied by nausea.
Signs of significant dehydration: passing very little urine, dizziness on standing, a dry mouth with sunken eyes, or lethargy.
Inability to keep any fluid down for more than 24 hours, which matters sooner in young children, older adults and people with diabetes.

Rehydration that actually works

The instinct to drink a large glass of water usually triggers another episode. Small volumes taken often are tolerated far better: a few sips every ten to fifteen minutes, increasing gradually once they stay down. Plain water alone is not ideal after repeated vomiting because it replaces neither salt nor glucose; oral rehydration salts, which contain both in the proportions that drive absorption, are more effective and are inexpensive. Fizzy drinks and undiluted fruit juice are poor choices, as their sugar concentration can worsen diarrhoea if that is present too.

Medicines and blood sugar during illness

Vomiting complicates several long-term medications. People with diabetes should not simply stop insulin when unable to eat, as the risk of ketoacidosis rises; the usual advice is to keep testing and seek guidance rather than omit doses. Diuretics, ACE inhibitors, ARBs and metformin are often paused temporarily during significant vomiting or diarrhoea because of the strain on the kidneys, but that decision belongs to your prescriber. If you take steroids long term, vomiting is a specific reason to seek advice quickly, because doses may need to be increased rather than skipped.

Nausea & Vomiting: Common Causes and When It's Serious