What Are the Causes of Nausea?

Nausea is the body's sensation of wanting to vomit. Nausea isn't a disease or an illness but is often the symptom of another disease or illness. Many activities and conditions can cause nausea, including motion sickness, overeating, fear, severe pain and external sensations such as smells and sights. Nausea and vomiting are also the body's natural response to expel toxins. Drugs can limit nausea.

Motion Sickness

• There are a few types of motion sickness. Seasickness, car sickness, and air sickness are some and all are a result of the body's inability to match sensory information with the vestibular gland's sense of balance. A rocking boat or reading in a car creates these different perceptions of movement which can cause nausea. If a person is prone to one motion sickness, she may not be prone to all of them. Sometimes, a person can feel nauseous sitting in the back of a vehicle but feel fine sitting in the front.

Food Poisoning

• Nausea is also a symptom of some food poisonings. Campylobacter infection is a bacteria transmitted by eating contaminated food, water, milk, and through contact with infected babies or animals. Nausea is one of the symptoms associated with the illness. The body can usually recover on its own. Salmonella is another food poisoning that causes nausea.

Pregnancy

• Pregnancy can create a problem called "morning sickness" because the nausea is at its worst in the morning. The reality is this nausea can occur at any time during the day, or may even last all day. About 75 percent of all women experience nausea during their first trimester. The cause for nausea during pregnancy is unknown, but doctors believe it is a combination of many physical changes happening at once.

External Sensations

• Sometimes when the body perceives a noxious odor, taste or sight, it can trigger anxiety and nausea. In cases of visual stimulus, the anxiety is psychological and differs from person to person. If nausea occurs after tasting a food, nausea can be a warning sign of ingesting a dangerous substance.

Medical Conditions

• Nausea can be an indicator that a more serious illness is present. Nausea because of concussions, brain tumors or meningitis requires immediate medical attention. Nausea also can occur because of intense pain, like a broken bone or sprained ankle. In certain cases, drugs can be used to help alleviate pain or treat nausea.