Cod liver oil is obtained from the livers of fresh or frozen cod (Gadus morhua L.). This species is mainly caught off the coast of Norway and Iceland.
The oil is extracted by boiling and then cold filtration.
Medicinal cod liver oil is subjected to molecular distillation and the final product is light colored, oily, very smooth and a pale, yellow white, bright and almost odourless.
The veterinary cod oil is not distilled and the finished product is yellow to reddish yellow, with the characteristic odour of fish.