In recent years there have been certain scare stories about the possible negative effects on human health from some of these materials. However, today, it is realised that it is often not the polymers themselves, but their monomers or the additives used that are responsible for these negative effects. And the reality is that a lot of polymers are used in medical applications without adverse effects on patients. Hence, the dividing line between whether something is toxic and harmful to health or not (and if it is, under what conditions) is a very critical issue and therefore, there needs to be a better understanding of these systems. This book presents the available information on the eternal triangle of plastics and rubber and health, to enable a better understanding of the facts.