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Magic bullet

Paul Ehrlich and Sahachiro Hata, 1910.

Paul Ehrlich and Sahachiro Hata, 1910.

Credits:Wellcome Library, London.

In the 1800s medical scientists discovered micro-organisms, such as staphylococci and streptococci, were causes of disease, and began to investigate them with microscopes. The physician Paul Ehrlich, who worked in Robert Koch's bacteriology lab, searched for chemicals that would stain specific germs to make them more visible under the microscope. He reasoned that he could not only stain but also attack these germs if he could find a chemical that would both attach itself to the germ and kill it. He called these chemicals ‘magic bullets’. (According to an old superstition, bullets could be charmed to make sure that they would hit a particular person.)

Ehrlich intended that his modern, chemical version of ‘magic bullets’ would hit the specific germ, but not damage anything else in the patient's body. Ehrlich and his co-workers tried hundreds of chemicals on the microbes that caused syphilis. In 1909, Ehrlich's new colleague Sahachiro Hata (1873-1938) brought with him a method of producing syphilis infections in laboratory rabbits, and discovered that drug no. 606 worked. The first ‘magic bullet’ had been found, and was marketed under the name Salvarsan. Encouraged by this success, Ehrlich and other scientists, such as the German physiologist Emil von Behring, proposed that researchers should develop specific drugs to target specific germs, attacking the cause of the disease directly, rather than treating the symptoms.


T Lenoir, 'A magic bullet: research for profit and the growth of knowledge in Germany around 1900', Minerva, 26/1 (1988), pp 66-68

J Mann, The Elusive Magic Bullet: The Search for the Perfect Drug (Oxford: Oxford University Press, 1999)



A tiny single-celled living organism too small to be seen by the naked eye. Micro-organisms that cause disease are called bacteria.


The study of a group of single-celled organisms called bacteria.


A technique in which cells or thin sections of biological tissue are placed in coloured dyes (stains) to make them visible through a microscope. Staining heightens the contrast between transparent cell or tissue components.


The science of the functioning of living organisms and their component parts.