In the previous chapters, we have discussed some ways of determining the most credible diagnosis in a patient who could be identified by his set of clinical symptoms. The same symptoms are usually found in several illnesses. Therefore, it is often difficult to recognize the value of each of their deterministic yet individual characteristics all at once. After improving the diagnostic model by adding complementary solutions we are at last aware of a diagnosis of the patient. The next step would be to prescribe him medication that will lead to a cure. It is seldom possible to give the patient only one remedy to remove completely all unfavourable symptoms. In order to broaden a list of medicines that complement each other, we usually want to evaluate levels of one medicine and its impact on all of the symptoms. Preferably, we want to estimate the lowest and the highest levels of effectiveness of the medicines tested, one by one, when considering their curative powers. © 2007 Springer.