The authors report their experience with 60 patients treated for lumbar disc herniation by chemonucleolysis with chymopapain and followed-up 1 to 3 years after treatment. Long-term results were as follows: excellent: 50%; good: 40%; fair: 8.2%; poor: 1.8%. The high percentage of positive results is attributed to the rigid criteria for patient selection used, which resulted in treatment by chemonucleolysis in only 18.6% of the surgical cases of lumbar disc pathology observed. 27.2% of the patients treated complained of disorders which resulted in postoperative complications and/or prolonged convalescence: prolonged low back pain and vertebral stiffness in 20%, persistent contralateral sciatic pain in 5.4%; intense but transitory worsening of the sciatica in 1.8%. The most feared complication of chemonucleolysis is paraplegia occurring after the inadverted injection of the enzyme into the spinal fluid. This risk overshadows the positive attributes of the method. The most important advantage of chemonucleolysis, as compared with surgery, is that it avoids epidural scarring and permanent postoperative anatomical changes. Patients may benefit from these advantages, but they must be willing to accept the negative aspects of the method, as well.