- Is Flaxseed Oil the Same as Linseed Oil? There has been some confusion between these. Flax oil is also called linseed oil which is sold in hardware stores as varnish. Flaxseed and linseed are often used interchangeably but there is an important difference. North Americans use flaxseed to describe flax when used for human consumption and linseed to describe when it has been processed for industrial purposes.