The use of chemotherapy as a treatment for cancer goes back to the discovery of nitrogen mustard, a chemical warfare agent. Autopsy observations of people exposed to mustard gas revealed profound lymphoid and myeloid suppression, so the United States Department of Defense recruited two pharmacologists, Louis S. Goodman and Alfred Gilman, to investigate potential therapeutic applications of chemical warfare agents.

Given the effects of mustard gas on lymphoids and myelois, Goodman and Gilman reasoned that the agent could be used to treat lymphoma, since lymphoma is a tumour of lymphoid cells.

Goodman and Gilman first set up an animal model, i.e. they established lymphomas in mice, and demonstrated that they could treat them with mustard agents. Next, in collaboration with a thoracic surgeon, Gustav Linskog, they injected a related agent, mustine, the prototype nitrogen mustard anticancer chemotherapeutic, into a patient with non-Hodgkin's lymphoma. They observed a dramatic reduction in the patient's tumour masses. Although the effect lasted only a few weeks, it was the first step in the realization that cancer could be treated by pharmacological agents (Goodman et al 1946).