Silymarin, a flavonolignan contain phenolic and flavanoid component from Silybum marianum plant, is used for the strengthening against various liver conditions in both experimental models and clinical settings. Silybum marianum (milk thistle) has been used for centuries as an herbal medicine for the treatment of liver disease. Its use for various liver disorders due to drug as well as environmental factors. Silybum marianum contains silymarin, which is composed of the flavanolignans silybin, silydianin, and silychristine, with silybin being the most biologically active. Number of studies has established the cancer chemo preventive role of silymarin in both in vitro and in vivo models. Silymarin modulates imbalance between cell survival and apoptosis through intervention with the expressions of cell cycle regulators and proteins involved in apoptosis. Silymarin was found to be effective in the illness of organs like brain, prostate, lungs, heart, kidneys, pancreas and others. Silymarin act mainly by its antioxidative and free radical-scavenging properties, recently new molecular mechanisms based on the specific receptor interaction were discovered – e.g., modulation and inhibition of drug transporters, estrogenic receptors, P-glycoprotein, nuclear receptors and some others