Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of the throat.Over 30 definitions of nausea were proposed in a 2011 book on the topic.Nausea is a non-specific symptom, which means that it has many possible causes. Some common causes of nausea are gastroenteritis and other gastrointestinal disorders, food poisoning, motion sickness, dizziness, migraine, fainting, low blood sugar, anxiety, and lack of sleep. Nausea is a side effect of many medications including chemotherapy, or morning sickness in early pregnancy. Nausea may also be caused by disgust and depression.Medications taken to prevent and treat nausea and vomiting are called antiemetics. The most commonly prescribed antiemetics in the US are promethazine, metoclopramide, and the newer ondansetron. The word nausea is from Latin nausea, from Greek ναυσία – nausia, "ναυτία" – nautia, motion sickness, "feeling sick or queasy". Causes
Gastrointestinal infections (37%) and food poisoning are the two most common causes of acute nausea and vomiting. Side effects from medications (3%) and pregnancy are also relatively frequent. There are many causes of chronic nausea. Nausea and vomiting remain undiagnosed in 10% of the cases. Aside from morning sickness, there are no sex differences in complaints of nausea. After childhood, doctor consultations decrease steadily with age. Only a fraction of one percent of doctor visits by those over 65 are due to nausea.
According to Apollodorus, the Cyclopes also provided Poseidon with his trident and Hades with his cap of invisibility, and the gods used these weapons to defeat the Titans. Although the primordial Cyclopes of the Theogony were presumably immortal (as were their brothers the Titans), the sixth-century BC Hesiodic Catalogue of Women, has them being killed by Apollo. Later sources tell us why: Apollos son Asclepius had been killed by Zeus thunderbolt, and Apollo killed the Cyclopes, the makers of the thunderbolt, in revenge. According to a scholiast on Euripides Alcestis, the fifth-century BC mythographer Pherecydes supplied the same motive, but said that Apollo, rather than killing the Cyclopes, killed their sons (one of whom he named Aortes) instead. No other source mentions any offspring of the Cyclopes. A Pindar fragment suggests that Zeus himself killed the Cyclopes to prevent them from making thunderbolts for anyone else.The Cyclopes prowess as craftsmen is stressed by Hesiod who says "strength and force and contrivances were in their works." Being such skilled craftsmen of great size and strength, later poets, beginning with the third-century BC poet Callimachus, imagine these Cyclopes, the primordial makers of Zeus thunderbolt, becoming the assistants of the smith-god Hephaestus, at his forge in Sicily, underneath Mount Etna, or perhaps the nearby Aeolian Islands. In his Hymn to Artemis, Callimachus has the Cyclopes on the Aeolian island of Lipari, working "at the anvils of Hephaestus", make the bows and arrows used by Apollo and Artemis.