The immune system is one of the body's most important structures, ensuring its safety and integrity throughout the life of the microorganism. It is well known that secondary immunodeficiency is formed in infectious, surgical, somatic, and many other pathologies requiring adequate measures. Correlation of immunodeficiency conditions is carried out, as a rule, with medicinal products of plant, animal origin or preparations of synthetic nature. In addition to medications, various physical factors are used to restore disorders in the immune system, such as laser, ultrasound radiation, and electroactivated aqueous solutions. Mineral waters and hot sand (psammotherapy) are used in the honor of preventive and therapeutic agents for many diseases. At the same time, there are practically no works in the available literature devoted to an in-depth study of the effect of mineral waters, and hot sands (psammotherapy) on the hematopoietic and immune systems of the body in normal and immunodeficient conditions. The monograph is intended for use by independent researchers, basic doctoral students, research interns, master's and bachelor's students, as well as professionals.