Lateral X-rays of lumbosacral spines of 76 patients who received chymopapain injection for lumbar disk lesions after a positive myelogram and diskogram were examined and measured to determine the degree of narrowing which occurred after injection of the enzyme. There were 2 groups of patients, those with clinically good results after injection, and those with poor results. Measurements were made of the injected and adjacent noninjected disk spaces. The validity of the method used with established by a correlation of 0.95 over a period of time for the uninjected disks. The narrowing after injection was significant at the p less than 0.01 level for both clinical successes and failures, but the degree of narrowing was significantly greater for the clinically good results.