ABSTRACT
INTRODUCTION Most of the data about bioavailability of orally administered drugs are obtained in healthy individuals. However, many drugs are actually administered to patients in whom the underlying disease might affect either their absorption or their overall bioavailability. This is particularly true for patients suffering from diseases of intestinal absorption and digestion. In spite of a great potential importance for both clinicians and pharmacists, only a few reviews on this topic have appeared in the literature (1,2). Therefore, the aim of this chapter is to point out some gastrointestinal and systemic diseases that may affect drug absorption in humans.
