Plants are used to cure many diseases due to their therapeutic properties. The history of phytotherapy applications, in which plants are used for treatment, goes back thousands of years. The reason why plants have been used for treatment for such a long time; they have produced secondary compounds with thousands of different structures that have therapeutic properties. Many of the secondary metabolites produced by plants have been converted into drugs by rational phytotherapeutic applications. The demand for herbal medicines is increasing day by day all over the world due to the serious side effects of synthetic drugs used in the treatment, the inability to provide sufficient efficacy and the existence of diseases that still have no cure. There are nearly 13 thousand plant taxa in our country, and very few of the plants are used for medicinal purposes. In fact, thousands of plants and tens of thousands of secondary compounds that can be used for treatment are waiting to be discovered. The discovery of new, effective and safe herbal medicines is a remarkable research area today, and the discovery of effective and safe alternative medicines will provide a great benefit for human health.