Although scientific evaluations for product bioavailability performance have been routinely employed in most European and North American countries, debate continues on the potential problems in bioavailability and bioequivalency of pharmaceutical products in Hong Kong. Data obtained from these evaluations not only confirms the quality of the drug products in the market, but also permit a more rational selection of pharmaceutical products to achieve cost-effectiveness. It is well known that chemical equivalency may not necessarily imply bioequivalency due to the interplay of various formulation, pathophysiological and physicochemical factors. This paper will discusses some of the basic concepts and implications of these evaluations.