Use of essential fatty acids containing at least 25% of a mixture of eicosapentaenoic acid ethyl ester (EPA) and docosahexaenoic acid ethyl ester (DHA) in the preparation of a medicament for preventing mortality in a patient who had suffered myocardial infarction is new. Independent claims are included for: (i) use of essential fatty acids containing at least 25% of EPA or DHA in the preparation of a medicament for preventing mortality in a patient who had suffered myocardial infarction； (ii) a method for preventing mortality in a patient who has survived myocardial infarction comprising administration of a mixture of essential fatty acids containing at least 25% EPA+DHA； (iii) a method for preventing mortality in a patient who has survived myocardial infarction comprising administration of a mixture of essential fatty acids containing at least 25% of EPA or DHA.
