Clinical observations on ciguatera were collected between 1964 and 1977 on 3,009 patients from several South Pacific island groups. Patients generally presented with neurologic symptoms such as parasthesia, vertigo, and ataxia, in addition to gastrointestinal symptoms such as diarrhea, abdominal pain, nausea, and vomiting. Patients with this illness usually became symptomatic less than 24 hours after ingestion of the fish and most patients (76.8%) developed symptoms in less than 12 hours. Significant differences in certain symptoms were noted between Melanesian and Polynesian ethnic groups, suggesting a susceptibility difference, or a difference in the nature of the toxin found in different areas of the Pacific. Being poisoned multiple times appeared to result in a clinically more severe illness than disease observed in patients experiencing ciguatera for the first time.