The objective of the work was to optimize the extraction of Spanish sage essential oil by supercritical fluid (SFE) and to obtain extract useful for medical applications, such as, the case of Alzheimer disease. Different extraction conditions were tested and the evolution of the extracted oil composition was monitored by GC-MS analysis for the different fractions recovered at fixed time intervals. A comparison with an extract obtained by conventional hydrodistillation (HD) was also proposed for comparison. Particularly, different pressure and temperature values (90 bar-40 degrees C, corresponding to a density of 0.48 g/ml, and 100 bar-50 degrees C, corresponding to a density of 0.38 g/ml), three flow rates (1.32 kg/h, 1.02 kg/h and 0.72 kg/h) and three particle sizes of the vegetable material (0.8 mm, 0.5 mm and 0.3 mm) were studied. The major compounds found in the extracts were camphor (45%), 1,8-cineole (15%), camphene (4%), borneol (4%), myrcene (3%) and alpha-pinene (2%). A mathematical model was successfully applied to correlate the experimental data.