: a pale yellow fatty oil obtained from the liver of the cod (Gadus morhua) and related fishes and used in medicine (as in the prophylaxis of rickets) chiefly as a source of vitamins A and D—compare fish-liver oil
Oil obtained primarily from the liver of the Atlantic cod and related fish. It is principally a mixture of the glycerides (seeglycerol) of many fatty acids, but its minor constituents, the fat-soluble vitamin A and vitamin D, give it its importance. It was once used to treat and prevent rickets, but the widespread fortification of milk with vitamin D in the United States and Europe beginning in the 1930s eliminated rickets as a significant public health problem. It is still used as a remedy for joint pain caused by arthritis and as a preventive of cardiovascular disease, although these benefits have not been proven scientifically. It is also used in feeds for poultry and other animals.