Basing on the known methods for measuring the proteolytic and antiproteolytic activities with the use of N-benzoyl-L-arginine-paranitroanilide, a synthetic substrate, the authors suggest measuring the bile proteolytic and antiproteolytic activities with the use of the same reagents. The examined parameters of the bile are calculated according to the formulae that rule out preliminary plotting of calibration curves. The inhibitory activity is expressed in kontrical antitrypsin activity units, the proteolytic one in the amount of paranitro-aniline per unit of time. Data on the normal proteolytic and antiproteolytic activities of the bile are presented.