Patients with familial dysautonomia (FD), also called Riley Day syndrome or hereditary sensory and autonomic neuropathy type III, suffer recurrent attacks of uncontrollable nausea and vomiting that can last several hours or days and are severely disabling. Hypertension, tachycardia and skin blotching frequently accompany these attacks. Our long-term objective is to develop an effective treatment for nausea and vomiting in patients with FD.