RESUMEN
About 70-80% of the world population relies on herbal products, especially in the developing countries. Herbal products are available in various dosage forms for different types of ailment. Contamination of medicinal plants with heavy metal is of great concern. Heavy metals are known to affect the normal physiological function when the level of heavy metals exceeds in plants or animals. It can cause various acute and chronic effects in living organisms. Silybum marianum commonly known as milk thistle is used for varieties of liver diseases. Concentration of Fe 375 mg/kg is found high in the blue capitulum's seeds and concentration of Cr 49.80 mg/kg is present high in the white capitulum's seeds from district Sawabi. Less concentration of Zn 32.00 mg/kg is determined in the blue capitulum's seeds from Karak, while high concentration 30.00 mg/kg of Mn is noted in blue capitulum's seeds from Charsadda. Copper concentration 27.15 mg/kg is recorded in blue capitulum's seeds from Charsadda. High concentration of Cd 1.00 mg/kg is present in white capitulum's seeds from Khyber agency, while concentration of Pb is not detected in white capitulum's seeds collected from Karak district