The paper begins by suggesting that the discovery of a theory involves not just the formulation of a theory, but some degree of justification of the theory as well. This will be illustrated by the example of the discovery of the special theory of relativity by Einstein. The paper then goes on to apply this approach to medicine. The discovery of a cure involves first the formulation of a theory to the effect that such and such procedure will result in the disappearance of a disease or condition without unacceptable harm to the patient. The discovery is not complete until a theory of this form (a cure theory) has been confirmed empirically. The final section of the paper will illustrate this general view of discovery by two case histories. The first is the discovery of the statins. The second concerns the drug thalidomide.