Background: Silymarin is composed of a mixture of flavonolignans derived from secondary plant metabolism. These constituents are present in substantial amounts in milk thistle [Silybum marianum (L.) Gaertn. (Asteraceae)] seeds. Silymarin has antioxidant properties that impact it with protective effects. Because of its chemoprotective effect against liver disease, silymarin is considered a complementary and alternative hepatoprotective medicine.BRMethods and Results: Coniferyl alcohol and taxifolin, the two precursors for silymarin biosyntesis, are derived from phenylpropane and flavonoid units, respectively. Coniferyl alcohol is synthesized via the monolignol biosynthetic pathway, whereas taxifolin is synthesized via the flavonoid pathway. Multiple variables, including related substrates, production, and activating enzymes require consideration to study the biosynthetic pathway of silymarin.BRConclusions: This review is helpful as it summarizes the probable biosynthetic pathways of silymarin and multiple related activating enzymes and substrates found in various plants. A further understanding of silymarin is expected to increase its industrial use value.