The subject of both sections of this chapter is complex. In the first place because after marketing the spectators in the therapeutic scene have a tendency to see different plays. Healthy people see something different from patients and the perspectives of governments, health insurers and manufacturers are all different. Furthermore we know that with respect to drug use important differences between countries exist and that intercultural and interethnic variations can have a decisive influence on the final outcome of drug use. It might therefore be good to first cite some figures to illustrate that in the modern world pharmaceuticals cannot and should not be considered as trivialities.

In most Western countries 70% to over 90% of visits to a general practitioner result in the writing of a prescription. Also in the Western world the prescription of 9 drugs on medical wards is common procedure and 20% of patients are using more than 4 agents in the period before they are admitted.

And finally, in the Western world total drug costs range between 6 and 10% of the health budget and in developing countries this percentage can even be much higher.

Drugs and vaccines can affect the outcome of disease in individual subjects and in populations. An example of this is shown in Fig. 1 relating to notifications of poliomyelitis in the UK. Poliomyelitis changed in the early 20th Century from a disease that was endemic in young children (infantile paralysis) to a disease that became epidemic in young adults (paralytic poliomyelitis). This change was associated with improvements in hygiene and sanitation which tended to limit the faecal–oral spread of the virus in infants and young children. As a result fewer children grew up with naturally acquired immunity and a pool of susceptible young adults accumulated in the population. Figure 1 shows the dramatic increase in notifications of poliomyelitis in the early years following World War II and the dramatic effect of the Salk killed virus vaccine which was given by injection and the Sabin live attenuated vaccine which was given orally. Many of the small number of cases reported after the vaccines had become available and were widely used had, in fact, been acquired overseas. Figure 1 shows the dramatic effect of the anti-poliomylitis vaccines on the incidence of the illness in the UK community. Figure 2 shows deaths due to all forms of tuberculosis in the UK from 1840 until near the end of the 20th Century. Horton Hinshaw and William Feldman's paper on “Streptomycin in treatment of clinical tuberculosis: A preliminary report” appeared in the Proceedings of the Mayo Clinic in 1945. For his work on antibiotics and the discovery of streptomycin Selman Waksman received the Nobel Prize in 1952. Streptomycin and the later anti-tuberculosis drugs made a very dramatic differerence to the prognosis of individual tuberculous patients in the early post-War years following their introduction into clinical medicine. However, the dramatic decline in the number of deaths due to tuberculosis in the years from 1940 to the end of World War II – as shown in Fig. 2 – was due to continuing improvements in hygiene, housing, sanitation, diet and the rising standards of living. Thus Fig. 2 very nicely demonstrates the dramatic effect of a very serious disease such as tuberculosis in response to improvements in the social environment of the community. The specific anti-tuberculosis drugs, once they became available, made a dramatic difference to the outcome of infection in individual patients and thus to the pool of infection affecting the UK community.