This study gives some aspect regarding the specific surface area of the Piatra Verde thermally activated natural zeolites. Taking into account the biological properties reported for the natural zeolites, we study the influence of thermal activations on the structural behavior of the raw material, aiming at the future preparation of control release systems. The samples were characterized following specific techniques: X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and pH measurements. Our results indicate that the specific surface area of the natural zeolites, increase with positives effect over adsorption.