From Atoxyl to Salvarsan: searching for the magic bullet

March 15th of 2004 marked the 150th anniversary of the birth of Paul Ehrlich. He was the founder of modern chemotherapy and in fact coined the word and invented the science of chemical therapy. He and his chemist Al fred Bertheim were the first people to do three things: (1) identify a substance, either man-made or from natural products, which showed promise in killing certain invading organisms; (2) determine the correct structure of the active compound in this substance, and (3) modify the chemical structure of this compound to make it more potent to invading organisms and less harmful to the host.