Linseeds are very nutrient-rich oilseeds of the plant "Linum usitatissimum" (Linum usitatissimum), which, among other things, play an important role in the feeding of horses. Linseed cakes, also known as linseed flakes, have certain characteristics and valuable substances, which are advantageous for the nutrition and the health of horses. In the following, we explain the beneficial effect of linseed cake for horses, how linseed flakes are fed and the truth about the widely discussed prussic acid in linseed.