Tetrodotoxin (TTX) poisonings are not infrequently seen in Taiwan, and several outbreaks have been recorded by the Poison Control Center (PCC)-Taiwan during 1988-1995. However, their demographic data, clinical features, and medical outcome have not been reported. A retrospective study analyzed the PCC data of TTX poisonings. All patients reported to the PCC-Taiwan as TTX poisoning from July 1988 through December 1995 were included. Excluding 2 incidents, the diagnosis of TTX poisoning was documented by identification of puffer fish and/or by the analysis of TTX in it. Patient age, sex, season of poisoning, substances ingested, incubation period, presenting symptoms, recovery time, and clinical outcome were analyzed. A total of 20 incidents involved 52 patients. Males outnumbered females (52% vs 41%) with sex undetermined in 4 patients. Most incidents occurred in the spawning seasons of puffer fish, eg March to May. Puffer fish ingestion accounted for 18 incidents; ingestion of gastropod mollusks and Gobius criniger were responsible for the other 2 incidents. Following ingestion of puffer fish and other poisonous marine animals, most symptoms developed within 6 h with complete recovery usually in 24 h. Symptoms of TTX poisoning were similar as those previously reported; however, unusual features, such as hypertension (24%), pinpoint pupils (4%), bronchorrhea and facial flush (2%), were also seen. The mortality rate was 13.5%. The violent neurotoxin is present in puffer fish and occurs in other marine animals. Without adequate therapy, patients may have serious morbidity or even succumb. Careful identification of puffer fish and other poisonous marine animals, as well as proper treatment of TTX poisoning patients, are mandatory to successfully handle cases of TTX poisoning.