Hyperemesis gravidarum (HG) is a rare and severe form of nausea and vomiting of pregnancy associated with significant costs and psychosocial impacts. The etiology of HG remains largely unknown, although maternal genetics and placental factors are suspected. Prompt recognition and treatment of HG are essential to minimize associated maternal and fetal morbidity. Diagnosis is made on the basis of typical presentation, with exclusion of other causes of severe nausea and vomiting of pregnancy. Validated clinical tools are available to assess severity of symptoms and guide plans of care. Evidence to guide management of HG is limited, but many nonpharmacologic and pharmacologic interventions are available with published guidelines to inform implementation. Care of the woman with HG requires compassion and acknowledgement of individual needs and responses to interventions.