Natures Aid Omega-3 Fish Oil Liquid contains high levels of Omega-3 Fatty Acids EPA and DHA. DHA contributes to the maintenance of a healthy heart, brain and vision. EPA contributes to the maintenance of a healthy heart. The fish used in Natures Aid Omega-3 Fish Oil derive from Anchovy, Sardine and Mackerel. They are sustainably sourced and are Marine Stewardship Council (MSC) certified providing a guarantee of sustainability and full traceability. The fish oil has been molecularly distilled to remove pollutants, such as heavy metals (including mercury), dioxins and PCB’s to ensure ultimate purity.