The phytotherapy or herbal medicine is the more ancient form of medical attention and refers to the medical use of the plants or their constituents. This work is based on the analysis of the plants referred by the population as useful in the treatment of hypertension, and its chemical composition scientifically proven. Following the line of research defined by Ministery of Public Health of Ecuador on Medications, Supplies, Knowledge and Use of Medicinal Plants, in the area 19 -National System of Health-, this research was conducted on 614 hypertensive adults through interviews. The people had an average of 58 years old, predominance of female (60.09%), with basic level of schooling (29.47%) and an average of 7.2 years of suffering high blood pressure disease. Approximately 58% of the interviewed population used medicinal plants to treat the hypertension, while 42% did not use or know about medicinal plants The most widely used plants were Matricaria recutita (chamomile), Plectranthus amboinicus (oregano), Cymbopogon citratus (herb luisa (lemongrass)) and Valeriana officinalis (valerian). Among these plants, Lemongrass is the only one which its effectiveness as anti-hypertensive has been proven. The 34.03% of used plants are purchased at the and only 16.12% grew them in their backyards. The most used part of the plant was the leave and infusion the way of preparation. As part of the antihypertensive treatment the interviewed mainly consume the drugs of the pharmacological groups ACE and the ARA-II; the major mentioned conditions were visual disorders. Stress, TAG and cholesterol were mentioned as factors of risk. The medicinal use of studied plants is supported by scientific literature that also support them traditional use. Concerning the chemical composition of plant derivatives, oregano contains aromatics and oxygenated compounds, as main constituents. Chamomile contains above all flavonoids, tannins and terpenoids, lemongrass has phenolic compounds and valerian is characterized by flavonoids and terpenoids. The use of the studied plants by the population is attributed to its sedative and relaxing effects, in case of excitation nerve.