Biologically active compounds in the monograph are substances that have the ability to regulate physiological processes in the body. There are plant species that are synthesized in animals and microorganisms. These substances include vitamins, antioxidants, essential oils, coumarins, phenolic compounds, flavonoids, gossypol derivatives, phytoncides, and phytoalexins. Vitamins are organic compounds of various chemical structures that are important for humans and animals. These compounds, which the body requires only in very small amounts (unlike proteins, fats, and carbohydrates), enter the enzyme molecule and participate in tissue metabolism. The monograph is intended for the study of biochemistry and the biochemistry of agricultural products for undergraduate students with a focus on biology, as well as the storage and primary processing technology of agricultural products.