Omega-3 fatty acids, especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are essential fatty acids that have been shown high potential for preventing many diseases and playing role in human health. Today, the epidemiological evidence for the effects of this group of fatty acids on oxidative stress-related disease including cardiovascular disease, many inflammatory diseases, various types of cancer, fatty liver, mental illness, etc., have been well studied and various studies have been conducted with different perspectives in this regard. These effects are mediated by various biological processes, including changes in the composition of cell membrane fat, gene expression, cellular metabolism, signal transmission, metabolite production, and so on. Omega-3s are essential for people in society, especially those in stressful situations (such as soldiers and military personnel) or depression (such as some veterans), and they are one of the few recommended supplements by the FDA. Therefore, the purpose of this review at first is to study the structure of omega-3 fatty acids and then review the performance of this group on various diseases (with more focus on their anti-inflammatory effects) and the health of the military staff.