Nausea is the stimulus or feeling of urgent vomiting. It is therefore a precursor or sign of vomiting. The body sends a signal with the nausea stimulus that something has been fed to it, for example, that it does not like and tries to get rid of the fed substance with the vomiting.

The nausea stimulus is a protective mechanism of our body. The nausea stimulus is transmitted via the so-called nausea centre, which is located in the brain stem of our brain. It can be stimulated by various signals. These include odours, balance, the psyche, toxins or increased pressure on the nausea centre.


The causes of nausea are manifold. Mostly harmless causes are behind the nausea stimulus. If a nausea stimulus only occurs without subsequent vomiting, this is often triggered by psychological factors such as disgust with smells or looking at them.

A nausea stimulus also occurs naturally in the context of a gastro-enteritis, which is caused by a viral or bacterial infection. Nausea also frequently occurs after excessive alcohol consumption. In the case of a nausea with accompanying vomiting, one should always consider whether one has possibly eaten spoiled food or similar.

Travel sickness, migraines or sunstroke can also cause nausea. Some people also suffer from a so-called irritable bowel syndrome, which is accompanied by various complaints of the gastrointestinal tract, such as abdominal pain, diarrhoea or even nausea and vomiting. These symptoms are aggravated by psychological stress/psychological stress in people suffering from irritable bowel syndrome.

A nausea with or without vomiting also occurs partly as an after-effect of a previous anaesthetic. Likewise, but usually more pronounced, this also occurs as a side effect of chemotherapy. A concussion can also cause headaches, nausea and vomiting.

In addition to these rather harmless causes, increased intracranial pressure, which can be caused by a tumour for example, can also lead to a nausea with vomiting, as the increased pressure irritates the nausea centre. If a nausea stimulus occurs, it is of course not necessary to immediately think of a brain tumour. Only when the nausea or vomiting cannot be explained in any other way can such a suspected diagnosis be considered.

Other symptoms of nausea

The most common accompanying symptom of a nausea is nausea. They often go hand in hand. The nausea usually occurs before the nausea stimulus.

As a result of the nausea, vomiting is often the result. In addition to the nausea, heartburn (burning/pain behind the breastbone) often occurs because the nausea often transports acidic stomach contents towards the mouth through the oesophagus. As the oesophagus is not designed for such an acidic pH value as the stomach, this is partly manifested as heartburn.

If the underlying cause of the nausea is a gastrointestinal infection, the nausea is usually accompanied by diarrhoea and sometimes also abdominal pain. Fever and sweating also occur frequently during an infection. Some people feel a strong nausea when brushing their teeth, so that they have to choke all the time.

This is of course very unpleasant. It is still not possible to say exactly where this choking comes from. It is possible that the gagging reflex, which is normally only triggered when the back wall of the throat is touched, is more pronounced in these people.

There are various measures that can alleviate the nausea when brushing teeth. Firstly, breathing through the nose instead of through the mouth helps to suppress the nausea stimulus. Trying different types of toothpaste can also help.

If necessary, a toothpaste can be found that does not cause nausea. Tastes and smells can also stimulate the nausea centre in the brain. A smaller toothbrush, for example a children’s toothbrush, can also help.

Some patients also report that the nausea does not occur when brushing the teeth with an electric brush. Bending the upper body forward while brushing the teeth can also relieve the nausea. Less toothpaste comes into contact with the sensitive mucous membrane of the throat.

Unfortunately, there is no uniform therapy recommendation against nausea when brushing the teeth. A nausea in the morning makes women in particular quickly think of a pregnancy in which morning sickness is a known symptom. However, a nausea or nausea in the morning can also occur without an existing pregnancy, for example before breakfast.

This nausea is then often caused by low blood pressure (circulatory weakness) and/or low blood sugar levels (hypoglycaemia). The intake of food and fluids at breakfast helps to normalise this. In other people, the reason for the nausea in the morning is again due to eating too early.

Some people still have no appetite after getting up early in the morning and have to force themselves to eat something, which sometimes leads to nausea. In these cases you should wait a little until you eat food. Smoking can also cause nausea.

This is often caused by smoking on an empty stomach. In this case, you should be particularly careful not to smoke before breakfast. Smoking can also cause circulation problems and thus nausea.

This is especially the case with smokers who smoke very little. Smoking can also cause nausea or vomiting during pregnancy. Of course, not every nausea that occurs during smoking is associated with a pregnancy. If you have the corresponding symptoms, you should also carry out our nausea self-test: