Some data about the use of medicinal plants in Bulgarian traditional medicine in the Middle Ages and in modern times are presented and the results of 40-year-long experimental-pharmacological investigations on many medicinal plants used in Bulgarian traditional medicine are reviewed. In-depth discussion is presented on the investigations of garlic (Allium sativum L.), a plant widely used by Bulgarian people for treating different diseases. Data from studies on a large number of plants used for treatment of hypertension, infectious diseases and as diuretic and spasmolytic remedies are summarized.