Colza oil is a nondrying oil obtained from the seeds of Brassica napus subsp. napus. (syn. Brassica napus var. oleifera Delile, Brassica campestris subsp. napus (L.) Hook.f. & T.Anderson.) Colza is extensively cultivated in France, Belgium, the United States, the Netherlands, Germany and Poland. In France, especially, the extraction of the oil is an important industry. In commerce, colza is a traditional rapeseed oil (with turnip rape oil, sarson oil, toria oil (Brassica rapa ssp.), and ravison oil), to which they are very closely allied in both source and properties. It is a comparatively nonodoriferous oil of a yellow colour, having a specific gravity varying between 0.912 and 0.920. The cake left after extraction of the oil is a valuable feed ingredient for pigs.
Colza oil was used in Gombault's Caustic Balsam, a popular horse and human liniment at the turn of the 20th century. (Note that the ingredients listed in this link are similar to, but not the same as, the list on the actual bottle).
Among the more unusual applications of colza oil is the calming of choppy seas, where the oil modifies the surface tension of the water and rapidly smooths the surface. For this purpose, colza oil was carried in ship's lifeboats. Rescue and recovery operations have been made far less risky in this way.
More recently, colza has been cultivated in Europe as an ingredient for biodiesel fuels, and is the primary source of biodiesel in Germany.