Resolvin D2 is an autacoid resolvin. Autacoids are chemical mediators including the families of resolvins and protectins, defined by their potent bioactions and novel chemical structures. The bioactive local mediators, or autacoids, that require enzymatic generation from the omega-3 essential fatty acid EPA were first identified in resolving inflammatory exudates in vivo and carry potent stereoselective biological actions. Resolvins of the E (RvE) series are derived from eicosapentaenoic acid (EPA). Those derived from docosahexaenoic acid (DHA) were termed resolvins of the D series, for example resolvin D1 (RvD1).Resolvins and protectins have specific stereoselective actions which evoke biological actions in the nanogram range in vivo and are natural exudate products. Resolvins and protectins as distinct chemical families join the lipoxins as potent agonists of endogenous anti-inflammation and are proresolving chemical mediators of interest in human disease as potential new approaches to treatment. The term resolvins (resolution-phase interaction products) was first introduced to signify that these new structures were endogenous mediators, biosynthesized in the resolution phase of inflammatory exudates, possessing very potent anti-inflammatory and immunoregulatory actions. These actions include reducing neutrophil traffic, regulating cytokine and reactive oxygen species, and lowering the magnitude of the response. In recent years, investigators have recognized inflammation as playing a key role in many prevalent diseases not previously considered to be of inflammatory etiology. These include Alzheimer's disease, cardiovascular disease, and cancer, which now join those well-appreciated inflammatory disorders such as arthritis and periodontal disease. Identifying the molecular mechanism(s) that underlie the many reports of the benefits of dietary omega-3 PUFAs remains an important challenge for nutrition and medicine. Thus, that these new mediator families, resolvins and protectins, are biosynthesized from EPA and DHA, act locally, and possess potent, novel bioactions is of interest to researchers.