Aloe vera (L.) Burm. F. (= Aloe barbadensis Miller) known as "the plant of immortality" in ancient Egypt is used in phytotherapy as moisturizer, antibacterial, antifungal, antiviral and antioxidant. In Argentina it grows in the form adventitious or cultivated, Aloe arborescens Mill., Aloe saponaria Haw. and Aloe ciliaris Haw. (Aloaceae). In order to contribute to the identification of the drug plant the morphoanatomical characterization of the leaf was carried out. These species were studied with optical microscopy and scanning electron microscopy and the histochemical characteristics were studied in order to identify the active compounds. Morphoanatomical characteristics of these species were determined through lineal and proportional (stomatal index) parameters.