Reviewed by The Wellness Team. Last reviewed October 2026.
Nausea is one of the most common reasons people search for medical advice, and one of the vaguest symptoms to pin down. Most of the time it passes on its own. Sometimes it is a signal worth investigating properly. This guide explains the common causes, the red flags, and what a GP can do about it.
What actually causes nausea
Nausea is not a diagnosis. It is a symptom with a long list of possible causes, and the pattern matters more than the sensation itself. The most frequent culprits are gut infections and food poisoning, which usually come with diarrhoea or vomiting and settle within a few days. Migraine often brings nausea with it, sometimes before the headache starts. Pregnancy is a common cause in the first trimester. Reflux and gastritis tend to cause a low-grade, lingering queasiness, often worse on an empty stomach. Anxiety can produce genuine, physical nausea through the gut-brain connection, and many medicines list nausea among their side effects, including some antibiotics, iron tablets and painkillers.
Less common causes include gallbladder problems, kidney infections, inner ear conditions such as vertigo and labyrinthitis, and blood sugar swings. A GP's job is to sort the likely from the unlikely using your history: when it started, what makes it better or worse, and what else is happening.
When nausea needs a doctor quickly
Most nausea is safe to watch for a day or two. Some patterns are not. Seek medical advice promptly if you have severe or worsening tummy pain, especially pain that moves to the lower right side; vomiting that will not stop or keeps you from keeping fluids down for more than 24 hours; signs of dehydration such as very dark urine, dizziness on standing or a dry mouth; blood in vomit or black, tarry stools; a severe headache with a stiff neck or confusion; unexplained weight loss alongside persistent nausea; or nausea with chest pain or shortness of breath.
If you are pregnant and cannot keep any food or fluid down, that needs assessment the same day.
Persistent nausea is worth investigating
Nausea that has dragged on for more than two weeks, or that keeps coming back, deserves a proper look rather than another week of hoping. A GP consultation for persistent nausea usually covers the full history, your medicines, your diet and stress levels, and a targeted set of blood tests where indicated. These can check for anaemia, infection, inflammation, liver and kidney function, thyroid problems and blood sugar issues. A pregnancy test is routine where relevant. Depending on the picture, the next step might be a stool test, a scan, or a referral.
The point of testing is to stop guessing. Most people with persistent nausea get a clear answer or a clear plan within one or two appointments.
What treatment looks like
Treatment depends on the cause, but there is more available than most people realise. Anti-sickness medicines can be prescribed where clinically appropriate and often bring fast relief while the underlying issue is addressed. Reflux-related nausea usually responds well to acid-suppressing treatment. Migraine-related nausea improves when the migraine itself is treated properly. Where anxiety is the driver, treating the anxiety settles the stomach. Dehydration from vomiting sometimes needs more than sips of water, and a GP can advise on rehydration and when stronger measures are needed.
For self-care while you wait: small sips of fluid often beat big glasses, plain food in small amounts is easier to tolerate, and lying flat soon after eating tends to make things worse.
To book or ask a question, message WhatsApp or call 020 3951 3429. A telephone appointment is £59, a video consultation is £150, and an in-person visit at our London clinic is £220. The GP can prescribe where clinically appropriate, arrange blood tests and refer you on if needed.
Questions people ask
Can a GP prescribe anti-sickness tablets online?
Yes, where clinically appropriate. A video or telephone consultation is usually enough for a GP to assess nausea, decide whether anti-sickness medicine is suitable and safe for you, and send a private prescription to a pharmacy. Anything suggesting a more serious cause will be picked up in the history and investigated first.
How long is too long for nausea?
As a rough guide, nausea lasting more than a few days without a clear cause, or recurring over more than two weeks, is worth a consultation. Persistent nausea is not something to normalise, and it usually has a findable cause.
Is nausea on an empty stomach something to worry about?
Morning nausea on an empty stomach is common with reflux, pregnancy and anxiety, and is rarely dangerous on its own. If it is persistent, getting worse, or comes with weight loss or pain, book an appointment rather than waiting it out.
When is nausea an emergency?
Nausea with crushing chest pain, severe sudden headache, confusion, fainting, or signs of severe dehydration needs urgent care. Call 999 in a life-threatening emergency.
If nausea is disrupting your week, you do not have to work it out alone. Message us on WhatsApp, call 020 3951 3429, or email team@thewellnesslondon.com. Same-day appointments are often available, and the GP will tell you honestly whether you need tests, treatment or simply reassurance.