A single plant species contains a huge number of potential bio-active molecules, which represent the end products of the plant metabolism. In the content of modern science, such molecules are considered the reason for the bio-activity of herbal medicines. The plant metabolism change constantly and the way an herbal medicine is prepared can strongly affect the final chemical composition of the remedy. Both aspect are relevant for the preparation of the so called pharmaceutical recipe. Current technologies allow the detailed analysis of complex mixture of natural products; therefore, a better understanding of even strange traditional practices toward the preparation of herbal medicines, could be better explained by next generation of open mind scientists.