A new transdermal delivery system that controls cellulitis is evaluated using reversed-phase high-performance liquid chromatography coupled with photodiode array detection. An extraction procedure and the validation of the analytical method to assay the active excipients from the Centella asiatica plant (asiaticoside, madacessic acid, and asiatic acid) are described. Excellent results ae obtained in terms of linearity, accuracy, and specificity of the analytical method.