**1. Introduction**

Modern living presents a challenge to maintaining good health due to the prevalence of various chronic lifestyle disorders. Medical herbs have received the welldeserved attention as a result of the rapidly shifting international health situation and the quick understanding of the negative consequences of improper food preparation and overmedication. Strong demand in foods that can act as medicines is a result of growing understanding of the importance of diet and the pursuit of well-being. Foods or dietary components known as "functional foods" or "neutraceuticals" can also provide health benefits above and beyond those of simple nutrition. Beyond what might be predicted from their typical nutritive value, functional foods improve health. One of the useful compounds that has attracted a lot of attention from researchers in recent years is flaxseed.

Flaxseed (*Linum usitatissimum* L.) is one of the predominant industrial oils seed crops grown in temperate climates. The terms flaxseed (*Linum usitatissimum* L.) and linseed are often used interchangeably. The seed oil of this oilseed crop is enriched in α-linolenic acid (ALA) (18:3cisΔ9,12,15). In addition to linolenic and linoleic acids, lignans, cyclic peptides, polysaccharides, alkaloids, cyanogenic glycosides, and

cadmium are among the numerous physiologically active substances and elements that concentrate in flaxseed. The majority of a-linolenic acid or lignan-containing extracts have been the subject of biological and clinical studies on flaxseed. In this chapter, we explain about the chemical characteristics and clinical effects of flaxseed in improving health and preventing chronic diseases.
