This is the protocol for a review and there is no abstract. The objectives are as follows:
1. To evaluate the efficacy and safety of pancreatic enzyme replacement therapy (PERT) in children and adults with CF.
2. To compare the efficacy and safety of different formulations of PERT and their appropriateness in different age groups.
3. To compare the effects of PERT in CF according to different diagnostic subgroups (e.g. different ages at introduction of therapy and different categories of pancreatic function).