Nausea and lightheadedness can be caused by a number of different things, not all of which are serious. They are both common symptoms of an illness such as the flu; they may also be caused by medical issues such as thyroid disorders, low blood sugar, high blood pressure, or diabetes, just to name a few. In many cases, though, these symptoms may have a simpler explanation, such as overindulgence in alcohol, eating food that was perhaps not prepared properly, or even from motion sickness such as what can occur after riding in a car, boat, or plane.
The flu is one of the most common causes of nausea and lightheadedness, and it will usually progress to a fever as well as body aches and pains. If these symptoms persist and are unexplained by any illnesses or recent lifestyle changes, it may be best to visit a doctor to rule out anything more serious. He or she will typically be able to do some tests and determine if the symptoms are cause for concern. In most non-serious cases, however, nausea and dizziness can be treated by getting some rest, taking some deep breaths in through the nose, and eating something bland such as plain crackers or sipping on ginger ale. If the symptoms are caused by low blood sugar, eating a snack or having some juice can help.
Drinking too much alcohol is one of the most common causes of stomach upset and lightheadedness. It may occur immediately after drinking, or it might not occur until the next morning. It is a good idea to drink a lot of water to rehydrate after drinking too much. Too much caffeine can also cause similar sensations.
Food poisoning is a common source of nausea and lightheaded, but it typically progresses to vomiting or diarrhea if the food was actually bad. Extreme pain, from an injury such as a broken bone, or blood loss, can also cause immediate nausea and lightheadedness. In addition, some people find that prolonged or acute stress can cause them to feel slightly nauseous or dizzy, and anxiety or panic attacks can cause these symptoms as well.
Motion sickness is another one of the most common causes of nausea and lightheadedness. Some people experience this on any form of transportation, while others will only feel ill on a boat or airplane, for example. It may be helpful to take ginger pills or motion sickness medication beforehand, to prevent the motion sickness from occurring. It is also helpful to take deep breaths and to look at a fixed point on the horizon to prevent the nausea from worsening.