If I remember correctly there is a difference between straight linseed oil and boiled linseed oil. I don't remember the finer points. I think boiled is cut with solvents.
Non-boiled linseed oil is edible and often added to horse feed to give them a shinny coat. "Boiled" linseed oil has had an acid added to it (it "boils" when that is done, thus the name), and is no longer edible. The boiled linseed oil is used as a finish for wood that will harden. Some claim that raw linseed oil never really dries, but is used to preserve/finish wood (mostly gun stocks), also.