The present invention is a non-invasive apparatus, system, and method for performing irradiation light therapy upon blood circulating within the nostrils of a living mammalian subject. The merit and medical value of the invention resides in its ability to achieve a reversal of red blood cell aggregation in-vivo without invading the tissues or organs of the living subject—a clinical result which leads to lower blood viscosity and improved blood circulation. In this manner, the invention provides the living mammalian subject with an enhanced immunity from diseases, a reduced vulnerability to hypertension, and a reduced risk of a cardiovascular incident. Furthermore, by altering the wavelengths transmitted by the light generating unit(s) and controlling the light energy dosage, the method and system can also fine-tuned further as intervention for various diseases.
