Nausea and vomiting commonly known as morning sickness in pregnancy is extremely common. During pregnancy normal nausea and vomiting may be evolutionary protective mechanism as it may protect the pregnant woman and her embryo from harmful substances in food such as pathogenic microorganisms in meat products and toxins in plants, these effects are maximal during embryogenesis the most vulnerable period of pregnancy. Studies suggest that women who had nausea and vomiting were less likely to have miscarriages and stillbirth. Hyperemesis gravidarum is rare but the most severe form of nausea and vomiting in pregnancy that may necessitate hospitalization. It is characterized by persistent nausea and vomiting associated with ketosis and weight loss (>5%) which may lead to volume depletion, electrolyte and acid base imbalances, nutritional deficiencies and even death.