Understanding What Causes Nausea

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Nausea is a sensation a person experiences when the stomach wants to empty itself, and vomiting is a forcible emptying of the stomach. Both are unpleasant and can throw a person’s day off. Nausea is not a condition, but a symptom of an underlying condition and it can be caused by a number of things. So, what causes nausea?

Acute Gastritis

This is an acute condition in which the lining of the stomach it irritated by an offending agent. The stomach flu is a common one. It is associated with a viral infection and is often characterized by diarrhea and vomiting. Food poisoning is also classified as acute gastritis and can last for one to two days. Bacterial toxins associated with consuming poorly prepared or contaminated foods are the most common cause and patients can experience significant vomiting.

Infections, whether a travel-related infection or a common virus, are common causes. They may cause fever, chills and abdominal pain. Rotavirus and noroviruses are common. Common parasitic infections that may cause nausea include those in the Helicobacter family.

Gastroesophageal reflux disease and peptic ulcer disease may cause acute gastritis. Other offending agents may include smoking, alcohol and non-steroidal anti-inflammatory drugs.


It seems that nausea is a possible side effect of just about every medication on the market, but there are certain medications that are more likely to cause nausea. In learning about what causes nausea, it is important to know which medications are more likely to cause it. Anesthesia medications that are used for surgeries and other medical procedures commonly cause nausea. Chemotherapy also commonly leads to nausea. Other medications known for causing nausea include antibiotics, opioid or narcotic pain medications, sedatives, muscle relaxing medications and any medication that works directly on the stomach, such as ulcer medications.

Central Causes

With a central cause, the brain is sending signals telling the body to be nauseous and to vomit. Headaches, specifically migraines, can cause nausea and vomiting. A head injury can also cause this symptom due to increasing intracranial pressure. Other conditions that may cause nausea related to intracranial pressure include concussion, meningitis, tumor in the head, encephalitis and an abnormal water or electrolyte balance in the bloodstream.

Inner ear problems can also cause this symptom. These may include motion sickness, benign postural vertigo, labyrinthitis and Meniere’s disease.

A noxious stimulus may cause this symptom. Heat related illnesses, such as extreme sunburn, heat exhaustion or dehydration can also cause nausea.

Medical Conditions

A large variety of medical conditions can cause nausea. Some of the most common ones include diabetes, hepatitis, pancreatitis, kidney diseases, lung infections, gallbladder disease, inflammatory bowel disease, certain types of cancer, heart attack, sepsis, bowel obstruction and eating disorders. Pregnant women may also experience nausea.


eMedicineHealth. (2011). Vomiting and Nausea. Retrieved on March 22, 2011 from eMedicineHealth: https://www.emedicinehealth.com/vomiting_and_nausea/article_em.htm

MedicineNet. (2011). Nausea and Vomiting. Retrieved on March 22, 2011 from MedicineNet: https://www.medicinenet.com/nausea_and_vomiting/article.htm