Arachidonic acid belongs to a kind of polyunsaturated omega-6 fatty acid, which is highly biologically relevant. It is abundantly distributed in brain, muscles and liver. It is the precursor for all prostaglandins, thromboxanes, and leukotrienes. Most cellular arachidonic acid is esterified in the membrane phospholipids. It is an important second messenger of cellular signalling participating in the regulation of signaling enzymes including PLC-γ, PLC-δ, and PKC-α, -β, and -γ isoforms. In addition, arachidonic acid acts as key inflammatory intermediate as well as avasodilator. Generally, the body can synthesize the arachidonic acid through linoleic acid. However, upon linoleic acid deficiency, it is necessary to supplement arachidonic acid from the diets. Food sources of arachidonic acid include meat, eggs and some fishes. Alternatively, we can also have arachidonic acid supplements.