Osteoarthritis and degenerative orthopedic diseases are an important health problem with an increasing incidence as a result of the change in population characteristics. Most of the conservative treatment methods that have been used for a long time, work as a palliative treatment. The need for drugs that will slow down the course of the disease and modify the disease process, rather than just alleviating the pain, has become more evident over time. Autologous conditioned serum (ACS) has also been proposed as a response to this need. The importance of interleukin-1 (IL-1) in degenerative musculoskeletal diseases, including osteoarthritis, has been understood with a more detailed examination of the basic pathophysiology of the disease. Interleukin-1 receptor antagonist (IL-1Ra), a natural inhibitor of IL-1, is a molecule secreted by monocytes. The blood taken for the preparation of ACS is treated with glass beads and incubated at 37 degrees. Thus, an increased amount of IL-1Ra is produced from monocytes in the blood, as well as anti-inflammatory cytokines and various growth factors. Limited amount of literature on ACS exists, which has been used in the treatment of various diseases since its introduction to the market. In this article, basic philosophy behind ACS, preparation of ACS, and its use in today`s orthopedic practice have been evaluated.