The study was aimed both at defining normal values of pancreatic function and at looking at variables (age, sex, body weight, height, and body surface) which may influence the range of normality in 271 normal controls evaluated consecutively by duodenal intubation from 1974 to 1981. Frequency distribution of all functional values were consistent with a Gaussian curve. A positive, linear correlation was found between secretory parameters and both volume secretion and output values, while no correlation was detected with bicarbonate and enzymes values. Duodenal fluid secretion and both bicarbonate and enzymes output were approximately 20% higher in males than in females, the difference being statistically significant. Mean values of both bicarbonate and enzyme concentration were not statistically different between sexes. When related to body surface, both volume and outputs values in males were no more different from those observed in females. The study has shown that body size influences pancreatic functional values and, therefore, the values should be related to some parameters of body size as body surface. The difference between males and females in fluid secretion and output values is linked primarily to differences in body size. The normal distribution of all functional parameters implies that normal limits may be calculated with standard parametric statistical analysis.