During the decade from 1976 to 1986, the age-related incidence of meconium ileus equivalent (MIE) was calculated on the basis of 240 Danish cystic fibrosis (CF) patients. In the first 5 years, the patients were given enteric-coated granules of pancreatic enzymes (Pancreatin, Rosco, Denmark), and a low fat diet was recommended. In the last 5 years, the Center recommended supplementation with acid-resistant, enteric-coated, encapsulated microspheres (Pancrease, Cilag, Birkerød, Denmark), and high-energy intake with a 40% fat content and no dietary restrictions. There was no difference in the incidence of MIE when these two 5-year periods were compared, and the overall incidence of MIE was low (5.4 MIEs/1,000 patient years). This may, at least in part, be due to the rather high intake of exocrine pancreas enzyme supplementation (EPES) (a mean intake of 0.9 capsules/kg/day). MIE occurred almost exclusively among patients greater than 15 years old and peaked in young adults aged 20-25 years (35.5 MIEs/1,000 patient years). The daily intake of EPES/kg of body weight declined significantly with age, and the patients who developed MIE received even less than average per day. Both of these points strengthen the view that a low enzyme dosage is likely to have an effect on the incidence of MIE.