PROBLEM TO BE SOLVED: To provide a new component useful for prophylaxis of sudden death or embryonic lethality caused by cardiac failure due to lipid oxidation.SOLUTION: This invention provides black vinegar and/or black vinegar unrefined lee powder as a new component to obtain following agents: (1) an agent for preventing sudden death caused by cardiac failure, (2) an agent for preventing embryonic lethality and (3) an agent for preventing sudden death or embryonic lethality caused by cardiac failure due to lipid oxidation.