Fish oils are the most common source of omega-3 polyunsaturated fatty acids (n-3 PUFAs), mainly eicosapentaenoic acid(EPA). It has been pointed out protective effects and beneficial effects of EPA on body weight reduction, heart health, blood lipid profile, cardiovascular diseases and other diseases. Based on its biological activities, EPA may be developed to a complementary and alternative medicine through further research. In this paper, the pharmacological effects of EPA were summarized by reviewing the recent related literatures.