Abstract: The medicinal and aromatic plants in particular the sheets of myrtle have much importance for the pharmacopeia, perfumery, the confectionery. This study enters within the framework of the valorization of this plant produced in Tunisian north. It is a question of studying the drying of this plant and the influence of this drying on the efficiency and the quality of essential oils. In order to determine the water content final to optimize the conditions of storage and drying of product, a determination of the isotherms of adsorption-desorption was carried out using the static gravimetric method. The curves obtained are then approached by empirical models. Another experimental study is devoted to the determination of the kinetics of drying under controllable conditions of temperature and moisture.