Vibrio vulnificus endotoxin was extracted, analyzed the chemical composition, tested its biological activity, and compared to those of Escherichia coli and Salmonella typhimurium. The major fatty acid of three endotoxins were different each other; V. vulnificus endotoxins were different each other; V. vulnificus endotoxin was myristric acid (C14:0), E. coli was lauric acid (C12:0), S. typhimurium was capric acid (C10:0). The biological activities of V. vulnificus endotoxin were similar to those of E. coli and S. typhimurium in terms of the gelation activity of the Limulus amebocyte lysate and the lethal toxicity. But the result of enzyme (AST, ALT, and LDH) analysis showed that the enzyme activity of V. vulnificus endotoxin was similar to that of E. coli, but smaller than that of S. typimurium.