AbstractNausea and vomiting of pregnancy affect the majority of pregnancies, while the most severe version, hyperemesis gravidarum (HG), affects a much smaller subset of women. Despite the prevalence of nausea and vomiting of pregnancy and the severe consequences of HG, the pathophysiology of these conditions is not fully understood. Currently, it is thought that a combination of hormonal factors accounts for their development. Multiple treatments have been described for nausea and vomiting of pregnancy and HG with varying levels of success. In this paper we describe the epidemiology of nausea and vomiting of pregnancy and HG, the recommended workup, their proposed etiologic factors, treatments, and their potential impact on mother and baby.