As Correa noted in Chapter 6, each new medicine has to undergo a complex and lengthy process of selection, testing and development in order to make it safe for human use and effective in terms of treatment. Following initial testing, using computers, test-tube methods and testing the molecule on animals (‘preclinical trials’), a promising compound begins three phases of clinical trials by an increasingly wide range of people in order to analyse its effects on the human body and its absorption, distribution, metabolism and excretion (Ballance et al, 1992; US Congress, 1993; Gambardella, 1995).