Chymopapain is a proteolytic enzyme derived from the papaya plant (Carica papaya) and has been used as a treatment for herniated lumbar intervertebral discs, a procedure known as chemonucleolysis. The rationale for its use is based on its ability to enzymatically digest the proteoglycan matrix of the nucleus pulposus within the spinal disc, thereby reducing disc volume and relieving nerve root compression. The procedure was first introduced in the 1960s and gained medical acceptance in the 1970s and 1980s, with several clinical studies and randomized controlled trials supporting its efficacy over placebo in reducing leg pain and improving mobility in patients with contained lumbar disc herniation.

However, the use of chymopapain declined sharply due to concerns about serious adverse events such as anaphylaxis, transverse myelitis, and other complications. The U.S. FDA approved its use in 1982 but later withdrew approval in 2003 due to declining use and safety concerns. Current clinical guidelines no longer recommend chymopapain chemonucleolysis as a standard treatment for herniated discs, largely because of these safety concerns and the success of alternative surgical and conservative treatments. While there is clear scientific evidence supporting its mechanism and some clinical efficacy, safety concerns and lack of current clinical use limit its rating to a moderate level.