Hydatidosis is a disease caused by the larval form of E. granulosus and it is usually endemic or highly endemic in countries that surround the Mediterranean Basin. It has a number of important economic and medical consequences. In many countries this disease is a major public health problem and can cause severe morbidity and mortality in humans. Chemotherapy has an important role not only on the treatment of individual patients, but also in conjunction with public health and vector-control measures. However, surgery remains the only reliable means of treatment for hydatid cysts, but it carries the risks of operative morbidity. Hence, it is suggested that alternated methods could be useful, one of these might be the use of plant extracts. This book, therefore, provides a new promising cure for this disease throughout the two plant extracts used in this work. Three separate experiments are carriedout essentially, based on the traditional uses of the natural products. This work should help shed light on these two plants which grow on Socotra island (Yemen), and should be useful to scientists in parasitology and pharmacognosy fields, or the workers in the traditional medicine.