Carboxytherapy (the treatment based on carbon dioxide injections) is a multipurpose and widely used medical technology. The use of CO2 injections (intracutaneous, subcutaneous, and pneumopuncture) have substantially supplemented and increased the practical relevance of carboxytherapy as a method for the treatment of many diseases. Thanks to it physiological properties, CO2 has antihypoxic, antioxidant, vasodilatory, anti-inflammatory, analgesic, and spasmolytic activities; moreover, it improves blood viscosity, stimulates neoangiogenesis, and regenerative processes. Carbon dioxide is a sort of biochemical «peacemaker» in tissue oxygenation: when blood cells are exposed to high CO2 concentrations (Bohr effect), the rate of gas exchange (CO2 and O2) increases. The human organism interprets carboxytherapy (local hypercapnia) as oxygen deficiency and responses to it by boosting not only the blood flow, but also the vascular endothelial growth factor which stimulates neoangiogenesis and in the long run improves blood supply and tissue trophism. The multiple mechanisms of action, polymodal efficacy, a tool kit with a wide range of detectors and various modes of treatment make carboxytherapy a popular medical technology all over the world, namely in cosmetology, dermatology, aesthetic medicine, angiology, orthopaedics, cardiology, neurology, pulmonology, gynaecology, urology, proctology, plastic and general surgery, and other areas. Carboxytherapy provides a perfect example of the off-label usage in medicine that made it one of the most extensively applied medical technology for the treatment of various diseases despite the lack of the preclinical data and scarce relevant information available in textbooks, reference books and booklets.