Herbal medicinal products are not only used for general well-being and to prevent or treat common minor ailments, but they are also used by individuals with serious chronic disease. Nowadays many patients are taking multiple grugs, herbs and vitamins concurrently which may interact with each other. It is necessary to know about possible herb-drug interactins, because of increasing tendency to using medicinal herbs all over the world. Interactions usually can be classified as pharmacokinetic (when the absorption, distribution, metabolism or elimination of one substance is affected by another) and pharmacodynamic (including antagonistic and synergistic interactions). An example of pharmacokinetic interaction is inhibition of Lithium absorption by psyllium because of high musilage content. Ginkgo increase anticoagulant activity of warfarin as a synergistic effect. In this article, interactions between 32 herbs and drugs are reviewed and presentsd in tables.