Nausea, or feeling sick, is a common complaint that can affect anyone at any age. Nausea can have many causes, including a stomach bug (gastroenteritis) and, during pregnancy, it can be a symptom of morning sickness.
Nausea is often followed by vomiting but usually clears up after two or three days without any need for treatment. If it continues for several days or you have repeated bouts, it might be a symptom of an underlying condition — this could be physical or psychological.
Nausea can be caused by conditions affecting your brain, gallbladder, liver, pancreas, oesophagus, small intestine or stomach. Diagnosing the underlying cause of persistent nausea can, therefore, be difficult.
In all cases, nausea is ultimately triggered by stimulation of a part of the brain called the vomiting centre. The vomiting centre causes the sensation of nausea and coordinates the act of vomiting.
Nausea is not painful but the symptoms are uncomfortable. Nausea can be felt in your chest, upper abdomen, back or throat. Other symptoms of nausea, such as headache, fatigue and loss of appetite, are common.
Other nausea symptoms include:
Many conditions can cause you to feel sick. If you also have diarrhoea and vomiting, you may have gastroenteritis (an infection of your stomach and bowel caused by a bacteria or virus), food poisoning or a virus such as norovirus.
If you also have a headache and a high temperature, you may have the flu.
Feeling sick often accompanies the intense headache of a migraine, along with vomiting and light and/or sound sensitivity.
It is also common to have nausea in the early weeks of pregnancy, although some women experience nausea into their third trimester.
Other common causes of nausea include:
Digestive system conditions
Motion sickness and seasickness
This can happen during a bumpy ride on any vehicle. Your inner ear, which is responsible for your balance, sends signals to your brain which do not sync up with the signals your eyes send to your brain. This can cause dizziness, nausea and/or vomiting.
Inner ear conditions
Your inner ear is responsible for your balance and awareness of your position and orientation in the world around you. Consequently, conditions that affect your inner ear can disrupt your balance, making you feel dizzy and nauseous.
Conditions include inner ear infections, such as labyrinthitis, and benign paroxysmal positional vertigo (BPPV), which is caused by loose debris in your inner ear.
You may experience nausea as a side effect of general anaesthesia. However, recent surgery can also cause nausea due to dehydration, taking medication post-surgery on an empty stomach and eating too much too soon after surgery.
Other nausea causes
Nausea can also be caused by conditions affecting your:
COVID-19 and nausea
The most common symptoms of COVID-19 are a dry cough, fever, loss of smell and taste and tiredness. Other symptoms include:
However, nausea is also a symptom of COVID-19 and the virus can cause other gastrointestinal symptoms often before you develop respiratory symptoms. These symptoms include:
Other accompanying symptoms and possible causes
Other symptoms associated with your nausea can give you a clue to the underlying cause. For example:
However, you should not self-diagnose. If you are worried, you should always see your GP.
With most bouts of nausea, you will stop feeling sick after a few hours to a few days. However, you should see your GP if your nausea continues, you are frequently nauseous or you are losing weight without trying.
To diagnose the cause of your nausea, your GP may examine your stomach and discuss how you feel. You might be asked to have blood and/or urine tests. If you are a woman, you might be asked to take a pregnancy test.
Your GP may refer you to a consultant for further investigations, diagnosis and treatment.
Nausea is rarely serious but it can occasionally be a sign of a heart attack. Seek medical assistance immediately if you suddenly feel nauseous and have:
Nausea can also be a sign of an infection, such as meningitis, so you should also seek medical assistance immediately if you have nausea and any of the following symptoms:
It is also necessary to seek medical advice for nausea if you suspect that you have ingested a poisonous substance or if you are dehydrated.
If you have nausea and have not been able to eat or drink for over 12 hours, or still have nausea after 24 hours of taking over-the-counter anti-nausea medication, see your GP.
If there is no improvement in how you feel after a few days, you should see your GP. They may prescribe anti-nausea medication and, if needed, will recommend treatment for the underlying cause of your nausea.
If your nausea is a side effect of medication, your GP or consultant may prescribe a different medication or change your dosage.
If you have morning sickness nausea or are pregnant and have nausea, you should always get advice from your midwife or GP before taking any medication.
If your nausea is caused by motion sickness eg when sitting at the back of the car, you can try sitting in the front. If your nausea occurs when travelling by sea, you can apply a scopolamine patch (anti-seasickness patch). You can also try over-the-counter medications, such as dimenhydrinate or an antihistamine.
If your nausea is caused by GORD, you can take stomach-acid reducers to relieve your GORD symptoms, which may, in turn, relieve your nausea. Similarly, if your nausea is caused by intense pain, taking painkillers may help relieve your nausea.
There are several changes you can make to ease your nausea symptoms yourself. You can try:
Try to avoid:
How should you sleep when nauseous?
If your nausea is caused by gastrointestinal symptoms or you feel like you want to be sick, it helps to sleep slightly inclined ie with your head raised a little.
Can constipation cause nausea?
Yes, constipation can cause nausea. When stools become backed up in your bowel, the discomfort can trigger nausea. Also, when stools remain in your bowel for too long, bacteria may increase in numbers and also trigger nausea.
What can cure hangover nausea and vomiting?
Alcohol dehydrates your body, as does vomiting. So it is important to stay hydrated by drinking lots of water. You can also try taking an antacid to calm down any gastric symptoms. You may feel weak and unwell if you did not eat properly while drinking. So try to eat a thin, vegetable-based broth to restore lost vitamins and minerals — avoid anything spicy or fatty as this will be harder to digest and may worsen your nausea.