Nausea

Nausea is a subjective sensation that is commonly experienced as the unpleasant urge to vomit. This sensation is coordinated by the brain, particularly in the chemoreceptor trigger zone (CTZ) and the vomiting center in the medulla. Various stimuli, including noxious smells, gastrointestinal irritation, motion sickness, pregnancy, and certain medications or toxins, can activate these brain regions. The feeling is often accompanied by autonomic symptoms such as increased salivation, pallor, and sweating. Nausea does not always lead to vomiting, which is the forceful expulsion of stomach contents through the mouth.

From a medical perspective, nausea is considered a non-specific symptom that can be indicative of a wide array of conditions ranging from acute infections, such as gastroenteritis, to chronic systemic illnesses like migraines or renal failure. It can also be a side effect of treatments like chemotherapy or radiation therapy. The assessment of nausea requires careful consideration of concurrent symptoms and medical history to determine the underlying cause, which guides the approach to treatment. Management of nausea may include pharmacological interventions, such as antiemetics, as well as lifestyle and dietary modifications.