Autologous platelet-rich plasma (PRP) therapies have seen a dramatic increase in breadth and frequency of use for orthopaedic conditions in the past 5 years. Rich in many growth factors that have important implications in healing, PRP can potentially regenerate tissue via multiple mechanisms. Proposed clinical and surgical applications include spinal fusion, chondropathy, knee osteoarthritis, tendinopathy, acute and chronic soft-tissue injuries, enhancement of healing after ligament reconstruction, and muscle strains. However, for many conditions, there is limited reliable clinical evidence to guide the use of PRP. Furthermore, classification systems and identification of differences among products are needed to understand the implications of variability.