Since the vegetarian diet lacks the substrate for pancreatic elastase-1 as an enzyme, a decreased secretion of this enzyme could be expected. We aimed therefore to assess the changes of exocrine pancreatic secretion in a prospective way in a group of healthy omnivores who modified their diet by abstaining from meat for 1 month. Twenty healthy omnivores (fourteen females and six males) were used in the study. The nutrient intake was assessed for 7 d before commencing the study (omnivore diet) and after 1 month of dietary modification (modified diet; meat excluded). Similarly, the faecal output of pancreatic enzymes (elastase-1, chymotrypsin and lipase) was assessed before and 1 month after the period of dietary modification. Statistical differences between two points of the assessment (paired data) were calculated with the use of the Wilcoxon rank test. The relationship between the changes of faecal enzyme output and the changes in nutrient intake was assessed using multiple regression analysis. The dietary changes resulted in statistically significant decrease of faecal elastase-1 output (P < 0·05), whereas for chymotrypsin and lipase no changes were observed. No significant change in stool weight was recorded. No statistically significant correlation between changes in energy and nutrient consumption and changes in faecal output of pancreatic enzymes has been found. It was concluded that the exclusion of meat from the diet for a 1-month period results in significant changes in pancreatic secretion with a selective decrease of elastase-1 output. However, the underlying factor remains unclear.