Carlson Wild Norwegian Cod Liver Oil is made of the finest cod liver oil from the unpolluted waters near Norway. Caught during the winter and early spring, the liver oil content is highest at this time of year. The oil is separated from the liver tissues without the use of chemicals. To insure freshness of Carlson Norwegian Cod Liver Oil, the air inside the glass bottle has been replaced with nitrogen and natural source vitamin E is added. Gluten free.