We begin our survey of pharmaceutical drugs with medicines that treat infectious disease – from sore throats and flu to TB and AIDS. Anti-infective drugs have been the trail-blazer for the pharmaceutical industry. Penicillin, for example, has probably been the most significant medical discovery of the 20th century. But, as we shall see, the fight against infection is far from over and we still desperately need drugs and vaccines to cope with major killers such as TB, malaria and AIDS.

The continuing world war

The course of human history has been shaped as much by microbes as by politicians, soldiers, and great thinkers such as Aristotle and Darwin. Smallpox alone has probably claimed more lives than any other disease in human history. Typhus among the troops was a deciding factor in Napoleon's retreat from Moscow in 1812, the English Civil War, and many important battles in Europe (World War II was the first major conflict in which more soldiers died in battle than from infectious disease). John Keats, George Orwell, and Vivien Leigh are only a few of the famous figures who have died prematurely of TB. And today the big killers such as AIDS and malaria are devastating the economies of developing countries – with knock-on effects for the rest of the world.

The war against infection will never be over. The latest figures issued by the World Health Organization (WHO) show that in 1995 17 million people – most of them children – died of infectious diseases. Pneumonia topped with list with four million deaths, followed by TB and malaria with 3.1 million deaths each.