In order to select the main medicinal plants used in folk medicine to treat arterial hypertension and/or diabetes, a survey was undertaken in different areas of oriental Morocco. The patients (370 women and 256 men) were divided into three groups: diabetics (61%), hypertensives (23%) and hypertensive diabetic persons (16%). On average, 67.51% of patients regularly use medicinal plants. This proportion is perceptibly the same in all groups and does not depend on sex, age and socio-cultural level. This result shows that phytotherapy is widely adopted in northeastern Morocco. For diabetes, 41 plants were cited, of which the most used were Trigonella foenum-graecum L. (Leguminosae), Globularia alypum L. (Globulariaceae), Artemisia herba-alba Asso. (Compositae), Citrullus colocynthis (L.) Schrad. (Cucurbitaceae) and Tetraclinis articulata Benth. (Cupressaceae). In the hypertension's therapy 18 vegetal species were reported, of which the most used were Allium sativum L. (Liliaceae), Olea europea L. (Oleaceae), Arbutus unedo L. (Ericaceae), Urtica dioica L. (Urticaceae) and Petroselinum crispum A.W. Hill (Apiaceae). Among the 18 species used for hypertension, 14 were also employed for diabetes. Moreover, these two diseases were associated in 41% of hypertensives. These findings suggest that hypertension observed in this region would be in a large part related to diabetes.