Cyclic vomiting syndrome (CVS) is a chronic functional condition of unknown pathogenesis. CVS is characterized as recurring episodes lasting a single day to multiple weeks. Each episode is divided into four phases: inter-episodic, prodrome, vomiting, and recovery. Inter-episodic phase (symptom free phase), is characterized as no discernible symptoms, normal everyday activities can occur, and this phase typically lasts one week to one month. The prodrome phase is known as the pre-emetic phase, characterized by the initial feeling of an approaching episode, still able to keep down oral medication. Emetic or vomiting phase is characterized as intense persistent nausea, and repeated vomiting typically lasting hours to days. Recovery phase is typically the phase where vomiting ceases, nausea diminishes or is absent, and appetite returns. This syndrome is most commonly seen in children usually between ages 3 and 7, however adult diagnosis is quite common. This disorder is thought to be closely related to migraines and family history of migraines. Signs and symptoms Affected individuals may vomit or retch 6–12 times in an hour and an episode may last from a few hours to over three weeks and in some cases months, with a median episode duration of 41 hours. Stomach acid, bile and, if the vomiting is severe, blood may be vomited. Some with the condition will ingest water to reduce the irritation of bile and acid on the esophagus during emesis. Between episodes, the affected individual is usually normal and healthy otherwise but can be in a weak state of fatigue or experience muscle pain. In approximately half of cases the attacks, or episodes, occur in a time-related manner. Each attack is stereotypical; that is, in any given individual, the timing, frequency and severity of attacks is similar. Some affected people experience episodes that progressively get worse when left untreated, occurring more frequently with reduced symptom free phase. Episodes may happen every few days, every few weeks or every few months, for some happening at common uniform times, typically mornings. For other affected people, there is not a pattern in time that can be recognized. Some with the condition have a warning of an episodic attack; they may experience a prodrome, some documented prodromal symptoms include: unusually intense nausea and pallor, excess salivation, sweating, flushing, rapid/irregular heartbeat, diarrhea, anxiety/panic, food aversion, restlessness/insomnia, irritability, depersonalization, fatigue/listlessness, intense feelings of being hot or chilled, intense thirst, shivering/shaking, retching, tachypnea, abdominal pain/cramping, limb