Hyperemesis gravidarum is most commonly seen in the first trimester. Weight loss usually accompanies vomiting and it is less common that the pregnancy-related nausea (0.3-3.6%). Environmental factors and genetic predisposition may play a role in the etiology. Furthermore it is thought that the increased placental load and elevated β-hCG levels also play a role in development of hyperemesis gravidarum. The psychological state of the patient might also aggravate the disease. Hyperemesis gravidarum is diagnosed clinically. This situation will threaten the woman's life besides having potential negative effects on the newborn health if it is not treated properly. The first step of treatment is diet and life style change. Intravenous hydration, electrolyte supplmentation and antiemetics can be used safely and efficiently.