This paper provides an extensive review of different aspects of five shellfish-poisoning syndromes (paralytic, diarrhoeic, amnesic, neurologic and azapiracid), as well as one fish-poisoning syndrome (ciguatera fish poisoning). It discusses in detail the causative toxins produced by marine organisms, chemical structures and analytical methods, habitat and occurrence of the toxin-producing organisms, case studies and existing regulations. Based on this analysis, risk assessments are carried out for each of the toxins, and recommendations are elaborated to improve the management of these risks in order to reduce the harmful effects of these toxins on public health. Contents Chapter 1: Introduction; Chapter 2: Paralytic Shellfish Poisoning (PSP); Chemical structures and properties, Methods of analysis, Source organism(s) and habitat, Occurrence and accumulation in seafood, Toxicity of PSP toxins, Prevention of PSP intoxication, Cases and outbreaks of PSP, Regulations and monitoring; Chapter 3: Diarrhoeic Shellfish Poisoning (DSP); Chemical structures and properties, Methods of analysis, Source organism(s) and habitat, Occurrence and accumulation in seafood, Toxicity of DSP toxins, Prevention of DSP intoxication, Cases and outbreaks of DSP, Regulations and monitoring; Chapter 4: Amnesic Shellfish Poisoning (ASP); Chemical structures and properties, Methods of analysis, Source organism(s) and habitat, Occurrence and accumulation in seafood, Toxicity of ASP toxins, Prevention of ASP toxins, Prevention of ASP intoxication, Cases and outbreaks of ASP, Regulations and monitoring; Chapter 5: Neurologic Shellfish Poisoning (NSP); Chemical structures and properties, Methods of analysis, Source organism(s) and habitat, Occurrence and accumulation in seafood, Toxicity of NSP toxins, Prevention of NSP intoxication, Cases and outbreaks of NSP, Regulations and monitoring; Chapter 6: Azaspiracid Shellfish Poisoning (AZP); Chemical structures and properties, Methods of analysis, Source organism(s) and habitat, Occurrence and accumulation in seafood, Toxicity of AZP toxins, Prevention of AZP intoxication, Cases and outbreaks of AZP, Regulations and monitoring; Chapter 7: Ciguatera Fish Poisoning (CFP); Chemical structures and properties of ciguatoxins, Methods of analysis, Source organism(s), habitat and distribution, Occurrence and accumulation in seafood, Toxicity of CFP toxins, Prevention of CFP intoxication, Cases and outbreaks of CFP, Regulations and monitoring; Chapter 8: Risk Assessment; Risk assessment for paralytic shellfish poisoning (PS), Risk assessment for diarrhoeic shellfish poisoning (DSP), Risk assessment for Amnesic shellfish poisoning (ASP), Risk assessment for neurologic shellfish poisoning (NSP), Risk assessment for azaspiracid shellfish poisoning (AZP), Risk assessment for ciguatera fish poisoning (CFP); Chapter 9: Conclusions and Recommendations; Conclusions, Recommendations.