The n-3 fatty acids have demonstrable biological activities and have been associated with many health improvements from child brain development to arthritis. In this review we sought to pull together the works that have examined the potential use of n-3 fatty acids in psoriasis. The rationale of using EPA and/or its metabolites is supported by findings which suggest that it has anti-inflammatory properties and plays an important role in the resolution phase of inflammation. EPA use in psoriasis has also been demonstrated in trials using oral, intravenous, and topical preparations, with generally positive outcomes. Depth profile analysis revealed that EPA and its metabolite, 15-HEPE are deposited in the epidermis, particularly in the metabolically active basal layer. This is considered advantageous in psoriasis therapy. Currently there are many unknowns about psoriasis aetiology and the effects of blocking different cytokines have on the disease progression. Furthermore not enough is known about EPA effects on cellular immunity other than via prostaglandin and leukotriene synthesis to fully understand the mode of action of EPA. However, evidence so far suggests EPA does have a potential role in the treatment of psoriasis, in particular for topical treatments either as an active anti-inflammatory agent by itself, or as a dual action permeation enhancer for other anti-psoriatic treatments. The challenges include optimising the delivery of EPA to the skin and determining the derivatives of EPA which would give maximal effects, and overcoming pharmacokinetic and formulation problems to optimally deliver EPA to its intended target cells.