Drug prices have become an important issue in the last few years as co
ncerns about constrained healthcare resources have increased. Healthca
re authorities in all industrialised countries are questioning whether
their country is carrying a heavier burden than others in paying for
drugs. In view of this discussion, several price comparison studies ha
ve been conducted. However, there is no generally accepted methodology
on how to conduct price comparisons, and many methodological issues r
emain unresolved. The results of most published studies are affected b
y moderately serious methodological flaws, which are never properly ad
dressed. The purpose of this study is to discuss the methodological is
sue of international drug price comparison, in terms of 6 points that
appear to this author to be necessary to conduct a methodologically so
und study. A previous review of a large number of drug price compariso
ns revealed that they all fail to take into account some or all of the
se 6 basic methodological points. Studies that fulfil the methodologic
al criteria outlined in this paper are therefore urgently needed befor
e drug pricing studies can be fully utilised as a basis for important
policy decisions in the healthcare arena.