In view of the situation that a clinically acceptablemedical agent which has the action of preventing andrelieving the lipotoxicity with no significant side effectsis not yet provided, such medical agent is provided. Anagent for relieving lipotoxicity which comprises anunsaturated fatty acid containing 18 to 22 carbon atoms andhaving a degree of unsaturation of 3 to 6 or a derivativethereof as its effective component.