Chymopapain (EC18.104.22.168, chymopapain A, chymopapain B, chymopapain S, brand name Chymodiactin) is a proteolytic enzyme isolated from the latex of papaya (Carica papaya). It is a medication used to treat herniated lower lumbar discs in the spine. Chymopapain injections are normally given under local, rather than general, anaesthesia. The dose for a single intervertebral disc is 2 to 4 nanokatals, with a maximum dose per patient of 8 nanokatals. The procedure is referred to as chemonucleolysis.
The sale and distribution of chymopapain was discontinued in the United States on January 27, 2003 after the company producing it decided to stop selling worldwide.