(all-Z)-5,8,11,14,17-Eicosapentaen-1-carbonitrile is an intermediate in the synthesis of (all-Z)-6,9,12,15,18-Heneicosapentaenoic Acid Ethyl Ester which is a fatty acid ester from marine oils; it is used for prophylaxis and treatment of hypertension, hypertriglyceridemia, hypercholesterolemia.